Patent
US 9,039,834NON-POLAR GALLIUM NITRIDE THIN FILMS GROWN BY METALORGANIC CHEMICAL VAPOR DEPOSITION
Michael D. Craven, James S. Speck
US
Copyright © 2026 Matter42. All rights reserved.
Patent
Atlas literature
Patent
US 9,039,834Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a flowchart that illustrates the steps of the MOC V D process for the growth of non-polar (11 2 0) a-plane GaN thin films on (1 1 20) r-plane sapphire, …
FIG. 2(c) is a schematic illustration of the epitaxial relationship between the GaN and r-plane sapphire;
FIGS. 3(a) and 3(b) are cross-sectional and plan-view transmission electron microscopy (TEM) images, respectively, of the defect structure of the a-plane GaN …
FIGS. 4(a) and 4(b) are atomic force microscopy (AFM) amplitude and height 5 images, respectively, of the surface of the as-grown a-plane GaN films.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
I. P. Smorchkova, C. R. Elsass, J. P. Ibbetson, R. Vetury, B. Heying, P. Fini, E. Haus, S. P. DenBaars, J. S. Speck, and U. K. Mishra, J. Appl. Phys. 86, 4520 (1999).
The method of claim 1, wherein the growth conditions and the substrate obtain the non-polar a-plane GaN film [[has]] having no c-plane content. currently amended
The method of claim 1, wherein the stacking fault density is at the top surface. previously presented
The method of claim 1, wherein the growth conditions obtain the non-polar a-plane GaN film with a stable a-plane orientation.
The method of claim 1, wherein the non-polar a-plane GaN film includes a thickness of 1.5 micrometers.
The method of claim 1, wherein growing the non-polar a-plane GaN film includes using 30 mol per minute Ga flow and 40,000 p mol per minute N flow, thereby providing a V/III ratio of approximately 1300. -4- G&C 30794.100- U S-C₁ SVG 13151491.04-15-2015.I₈J₉Y₉W₉PXXIFW3.CLM14214895.2.1227.3054.2214.3139.svg 0.283 3.29 Table Black and white 27.-28
O. Ambacher, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, W. J. Schaff, L. F. Eastman, R. Dimitrov, L. Wittmer, M. Stutzmann, W. Rieger, and J. 20 Hilsenbeck, J. Appl. Phys. 85, 3222 (1999).
I. Jin Seo, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, Phys. Rev. B 57, R₉₄₃₅ (1998).
R. Langer, J. Simon, V. Ortiz, N. T. Pelekanos, A. Barski, R. Andre, and M. Godlewski, Appl. Phys. Lett. 74, 3827 (1999). 25 5. P. Lefebvre, J. Allegre, B. Gil, H. Mathieu, N. Grandjean, M. Leroux, J. Massies, and P. Bigenwald, Phys. Rev. B 59, 15363 (1999).
P. Lefebvre, A. Morel, M. Gallart, T. Taliercio, J. Allegre, B. Gil, H. Mathieu, B. Damilano, N. Grandjean, and J. Massies, Appl. Phys. Lett. 78, 1252 (2001).
T. Takeuchi, C. Wetzel, S. Yamaguchi, H. Sakai, H. Amano, I. Akasaki, Y. 30 Kaneko, S. Nakagawa, Y. Yamaoka, and N. Yamada, Appl. Phys. Lett. 73, 1691 (1998).
P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, Nature (London 406, 865 (2000).
T. Sasaki and S. Zembutsu, J. App l e. Phys. 61, 2533 (1987).
C. J. Sun and M. Razeghi, App l. Phys. Lett. 63, 973 (1993). 5 11. T. Metzger, H. Angerer, O. Ambacher, M. Stutzmann, and E. Born, Phys. Status Solidi B 193, 391 (1996).
T. Lei, K. F. Ludwig, Jr., and T. D. Moustakas, J. App l e. Phys. 74, 4430 (1993).
C. R. Eddy, Jr., T. D. Moustakas, and J. Scanlon, J. App l e. Phys. 73, 448 10 (1993).
T. D. Moustakas, T. Lei, and R. J. Molnar, Physica B 185, 36 (1993).
K. Iwata, H. Asahi, K. Asami, R. Kuroiwa, and S. Gonda, Jpn. J. App l e. Phys., Part 2 36, L₆₆₁ (1997).
H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, App l. Phys. Lett. 48, 353 15 (1986).
K. Dovidenko, S. Oktyabrsky, and J. Narayan, J. App l e. Phys. 82, 4296 (1997).
B. Heying, X. H. Wu, A. S. Keller, Y. Li, D. Kapolnek, B. P. Keller, S. P. DenBaars, and J. S. Speck, Appl. Phys. Lett. 68, 643 (1996). 20 Conclusion This concludes the description of the preferred embodiment of the present invention. The following describes some alternative embodiments for accomplishing the present invention. For example, as the inclusions in the description above indicate, there are many 25 modifications and variations of the MOCVD technique and equipment that could be used to grow non-polar (1120) a-plane GaN thin films on (1 1 02) r-plane sapphire substrates. Moreover, different growth conditions may be optimal for different MOCVD reactor designs. Many variations of this process are possible with the variety of reactor designs currently being using in industry and academia. Despite these differences, the growth parameters can 30 most likely be optimized to improve the quality of the films. The most important variables 11 for the MOCVD growth include growth temperature, V/III ratio, precursor flows, and growth pressure. In addition to the numerous modifications possible with the MOCVD growth technique, other modifications are possible. For example, the specific crystallographic 5 orientation of the r-plane sapphire substrate might be changed in order to optimize the subsequent epitaxial GaN growth. Further, r-plane sapphire substrates with a particular degree of miscut in a particular crystallographic direction might be optimal for growth. In addition, the nucleation layer deposition is crucial to achieving epitaxial GaN films with smooth growth surfaces and minimal crystalline defects. Other than optimizing the fundamental MOCVD parameters, use of A l N or AlGaN nucleation layers in place of GaN could prove useful in obtaining high quality a-plane GaN films. Further, although non-polar a-plan GaN thin films are described herein, the same techniques are applicable to non-polar m -plane GaN thin films. Moreover, non-polar InN, Al N, and A l InGaN thin films could be created instead of GaN thin films. 15 Finally, substrates other than sapphire substrate could be employed for non-polar GaN growth. These substrates include silicon carbide, gallium nitride, silicon, zin c oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, and lithium gallate. In summary, the present invention describes the growth of non-polar (11 2 0) a-plane 20 GaN thin films on r-plane (1 1 02) sapphire substrates by employing a low temperature nucleation layer as a buffer layer prior to a high temperature growth of the epitaxial (1 120) a-plane GaN films. The epitaxial relationship is [0001]GaN 1[01] sapphire and [1100] GaN [11 20] sapphire with the positive GaN c-axis pointing in the same direction as the sapphire c- axis projection on the growth surface. 25 The foregoing description of one or more embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. 30 12 Claims What is claimed is:
canceled
canceled
canceled
Materials described outside the worked examples.
non-polar a-plane GaN
GaN
r-plane sapphire substrate
Al₂O₃
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Threading Dislocation Density | 26000000000 cm⁻² | GaN |
Stacking Fault Density | 380000 cm⁻¹ |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 9,039,834Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a flowchart that illustrates the steps of the MOC V D process for the growth of non-polar (11 2 0) a-plane GaN thin films on (1 1 20) r-plane sapphire, …
FIG. 2(c) is a schematic illustration of the epitaxial relationship between the GaN and r-plane sapphire;
FIGS. 3(a) and 3(b) are cross-sectional and plan-view transmission electron microscopy (TEM) images, respectively, of the defect structure of the a-plane GaN …
FIGS. 4(a) and 4(b) are atomic force microscopy (AFM) amplitude and height 5 images, respectively, of the surface of the as-grown a-plane GaN films.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
I. P. Smorchkova, C. R. Elsass, J. P. Ibbetson, R. Vetury, B. Heying, P. Fini, E. Haus, S. P. DenBaars, J. S. Speck, and U. K. Mishra, J. Appl. Phys. 86, 4520 (1999).
The method of claim 1, wherein the growth conditions and the substrate obtain the non-polar a-plane GaN film [[has]] having no c-plane content. currently amended
The method of claim 1, wherein the stacking fault density is at the top surface. previously presented
The method of claim 1, wherein the growth conditions obtain the non-polar a-plane GaN film with a stable a-plane orientation.
The method of claim 1, wherein the non-polar a-plane GaN film includes a thickness of 1.5 micrometers.
The method of claim 1, wherein growing the non-polar a-plane GaN film includes using 30 mol per minute Ga flow and 40,000 p mol per minute N flow, thereby providing a V/III ratio of approximately 1300. -4- G&C 30794.100- U S-C₁ SVG 13151491.04-15-2015.I₈J₉Y₉W₉PXXIFW3.CLM14214895.2.1227.3054.2214.3139.svg 0.283 3.29 Table Black and white 27.-28
O. Ambacher, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, W. J. Schaff, L. F. Eastman, R. Dimitrov, L. Wittmer, M. Stutzmann, W. Rieger, and J. 20 Hilsenbeck, J. Appl. Phys. 85, 3222 (1999).
I. Jin Seo, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, Phys. Rev. B 57, R₉₄₃₅ (1998).
R. Langer, J. Simon, V. Ortiz, N. T. Pelekanos, A. Barski, R. Andre, and M. Godlewski, Appl. Phys. Lett. 74, 3827 (1999). 25 5. P. Lefebvre, J. Allegre, B. Gil, H. Mathieu, N. Grandjean, M. Leroux, J. Massies, and P. Bigenwald, Phys. Rev. B 59, 15363 (1999).
P. Lefebvre, A. Morel, M. Gallart, T. Taliercio, J. Allegre, B. Gil, H. Mathieu, B. Damilano, N. Grandjean, and J. Massies, Appl. Phys. Lett. 78, 1252 (2001).
T. Takeuchi, C. Wetzel, S. Yamaguchi, H. Sakai, H. Amano, I. Akasaki, Y. 30 Kaneko, S. Nakagawa, Y. Yamaoka, and N. Yamada, Appl. Phys. Lett. 73, 1691 (1998).
P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, Nature (London 406, 865 (2000).
T. Sasaki and S. Zembutsu, J. App l e. Phys. 61, 2533 (1987).
C. J. Sun and M. Razeghi, App l. Phys. Lett. 63, 973 (1993). 5 11. T. Metzger, H. Angerer, O. Ambacher, M. Stutzmann, and E. Born, Phys. Status Solidi B 193, 391 (1996).
T. Lei, K. F. Ludwig, Jr., and T. D. Moustakas, J. App l e. Phys. 74, 4430 (1993).
C. R. Eddy, Jr., T. D. Moustakas, and J. Scanlon, J. App l e. Phys. 73, 448 10 (1993).
T. D. Moustakas, T. Lei, and R. J. Molnar, Physica B 185, 36 (1993).
K. Iwata, H. Asahi, K. Asami, R. Kuroiwa, and S. Gonda, Jpn. J. App l e. Phys., Part 2 36, L₆₆₁ (1997).
H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, App l. Phys. Lett. 48, 353 15 (1986).
K. Dovidenko, S. Oktyabrsky, and J. Narayan, J. App l e. Phys. 82, 4296 (1997).
B. Heying, X. H. Wu, A. S. Keller, Y. Li, D. Kapolnek, B. P. Keller, S. P. DenBaars, and J. S. Speck, Appl. Phys. Lett. 68, 643 (1996). 20 Conclusion This concludes the description of the preferred embodiment of the present invention. The following describes some alternative embodiments for accomplishing the present invention. For example, as the inclusions in the description above indicate, there are many 25 modifications and variations of the MOCVD technique and equipment that could be used to grow non-polar (1120) a-plane GaN thin films on (1 1 02) r-plane sapphire substrates. Moreover, different growth conditions may be optimal for different MOCVD reactor designs. Many variations of this process are possible with the variety of reactor designs currently being using in industry and academia. Despite these differences, the growth parameters can 30 most likely be optimized to improve the quality of the films. The most important variables 11 for the MOCVD growth include growth temperature, V/III ratio, precursor flows, and growth pressure. In addition to the numerous modifications possible with the MOCVD growth technique, other modifications are possible. For example, the specific crystallographic 5 orientation of the r-plane sapphire substrate might be changed in order to optimize the subsequent epitaxial GaN growth. Further, r-plane sapphire substrates with a particular degree of miscut in a particular crystallographic direction might be optimal for growth. In addition, the nucleation layer deposition is crucial to achieving epitaxial GaN films with smooth growth surfaces and minimal crystalline defects. Other than optimizing the fundamental MOCVD parameters, use of A l N or AlGaN nucleation layers in place of GaN could prove useful in obtaining high quality a-plane GaN films. Further, although non-polar a-plan GaN thin films are described herein, the same techniques are applicable to non-polar m -plane GaN thin films. Moreover, non-polar InN, Al N, and A l InGaN thin films could be created instead of GaN thin films. 15 Finally, substrates other than sapphire substrate could be employed for non-polar GaN growth. These substrates include silicon carbide, gallium nitride, silicon, zin c oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, and lithium gallate. In summary, the present invention describes the growth of non-polar (11 2 0) a-plane 20 GaN thin films on r-plane (1 1 02) sapphire substrates by employing a low temperature nucleation layer as a buffer layer prior to a high temperature growth of the epitaxial (1 120) a-plane GaN films. The epitaxial relationship is [0001]GaN 1[01] sapphire and [1100] GaN [11 20] sapphire with the positive GaN c-axis pointing in the same direction as the sapphire c- axis projection on the growth surface. 25 The foregoing description of one or more embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. 30 12 Claims What is claimed is:
canceled
canceled
canceled
Materials described outside the worked examples.
non-polar a-plane GaN
GaN
r-plane sapphire substrate
Al₂O₃
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Threading Dislocation Density | 26000000000 cm⁻² | GaN |
Stacking Fault Density | 380000 cm⁻¹ |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 9,039,834Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a flowchart that illustrates the steps of the MOC V D process for the growth of non-polar (11 2 0) a-plane GaN thin films on (1 1 20) r-plane sapphire, …
FIG. 2(c) is a schematic illustration of the epitaxial relationship between the GaN and r-plane sapphire;
FIGS. 3(a) and 3(b) are cross-sectional and plan-view transmission electron microscopy (TEM) images, respectively, of the defect structure of the a-plane GaN …
FIGS. 4(a) and 4(b) are atomic force microscopy (AFM) amplitude and height 5 images, respectively, of the surface of the as-grown a-plane GaN films.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
I. P. Smorchkova, C. R. Elsass, J. P. Ibbetson, R. Vetury, B. Heying, P. Fini, E. Haus, S. P. DenBaars, J. S. Speck, and U. K. Mishra, J. Appl. Phys. 86, 4520 (1999).
The method of claim 1, wherein the growth conditions and the substrate obtain the non-polar a-plane GaN film [[has]] having no c-plane content. currently amended
The method of claim 1, wherein the stacking fault density is at the top surface. previously presented
The method of claim 1, wherein the growth conditions obtain the non-polar a-plane GaN film with a stable a-plane orientation.
The method of claim 1, wherein the non-polar a-plane GaN film includes a thickness of 1.5 micrometers.
The method of claim 1, wherein growing the non-polar a-plane GaN film includes using 30 mol per minute Ga flow and 40,000 p mol per minute N flow, thereby providing a V/III ratio of approximately 1300. -4- G&C 30794.100- U S-C₁ SVG 13151491.04-15-2015.I₈J₉Y₉W₉PXXIFW3.CLM14214895.2.1227.3054.2214.3139.svg 0.283 3.29 Table Black and white 27.-28
O. Ambacher, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, W. J. Schaff, L. F. Eastman, R. Dimitrov, L. Wittmer, M. Stutzmann, W. Rieger, and J. 20 Hilsenbeck, J. Appl. Phys. 85, 3222 (1999).
I. Jin Seo, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, Phys. Rev. B 57, R₉₄₃₅ (1998).
R. Langer, J. Simon, V. Ortiz, N. T. Pelekanos, A. Barski, R. Andre, and M. Godlewski, Appl. Phys. Lett. 74, 3827 (1999). 25 5. P. Lefebvre, J. Allegre, B. Gil, H. Mathieu, N. Grandjean, M. Leroux, J. Massies, and P. Bigenwald, Phys. Rev. B 59, 15363 (1999).
P. Lefebvre, A. Morel, M. Gallart, T. Taliercio, J. Allegre, B. Gil, H. Mathieu, B. Damilano, N. Grandjean, and J. Massies, Appl. Phys. Lett. 78, 1252 (2001).
T. Takeuchi, C. Wetzel, S. Yamaguchi, H. Sakai, H. Amano, I. Akasaki, Y. 30 Kaneko, S. Nakagawa, Y. Yamaoka, and N. Yamada, Appl. Phys. Lett. 73, 1691 (1998).
P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, Nature (London 406, 865 (2000).
T. Sasaki and S. Zembutsu, J. App l e. Phys. 61, 2533 (1987).
C. J. Sun and M. Razeghi, App l. Phys. Lett. 63, 973 (1993). 5 11. T. Metzger, H. Angerer, O. Ambacher, M. Stutzmann, and E. Born, Phys. Status Solidi B 193, 391 (1996).
T. Lei, K. F. Ludwig, Jr., and T. D. Moustakas, J. App l e. Phys. 74, 4430 (1993).
C. R. Eddy, Jr., T. D. Moustakas, and J. Scanlon, J. App l e. Phys. 73, 448 10 (1993).
T. D. Moustakas, T. Lei, and R. J. Molnar, Physica B 185, 36 (1993).
K. Iwata, H. Asahi, K. Asami, R. Kuroiwa, and S. Gonda, Jpn. J. App l e. Phys., Part 2 36, L₆₆₁ (1997).
H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, App l. Phys. Lett. 48, 353 15 (1986).
K. Dovidenko, S. Oktyabrsky, and J. Narayan, J. App l e. Phys. 82, 4296 (1997).
B. Heying, X. H. Wu, A. S. Keller, Y. Li, D. Kapolnek, B. P. Keller, S. P. DenBaars, and J. S. Speck, Appl. Phys. Lett. 68, 643 (1996). 20 Conclusion This concludes the description of the preferred embodiment of the present invention. The following describes some alternative embodiments for accomplishing the present invention. For example, as the inclusions in the description above indicate, there are many 25 modifications and variations of the MOCVD technique and equipment that could be used to grow non-polar (1120) a-plane GaN thin films on (1 1 02) r-plane sapphire substrates. Moreover, different growth conditions may be optimal for different MOCVD reactor designs. Many variations of this process are possible with the variety of reactor designs currently being using in industry and academia. Despite these differences, the growth parameters can 30 most likely be optimized to improve the quality of the films. The most important variables 11 for the MOCVD growth include growth temperature, V/III ratio, precursor flows, and growth pressure. In addition to the numerous modifications possible with the MOCVD growth technique, other modifications are possible. For example, the specific crystallographic 5 orientation of the r-plane sapphire substrate might be changed in order to optimize the subsequent epitaxial GaN growth. Further, r-plane sapphire substrates with a particular degree of miscut in a particular crystallographic direction might be optimal for growth. In addition, the nucleation layer deposition is crucial to achieving epitaxial GaN films with smooth growth surfaces and minimal crystalline defects. Other than optimizing the fundamental MOCVD parameters, use of A l N or AlGaN nucleation layers in place of GaN could prove useful in obtaining high quality a-plane GaN films. Further, although non-polar a-plan GaN thin films are described herein, the same techniques are applicable to non-polar m -plane GaN thin films. Moreover, non-polar InN, Al N, and A l InGaN thin films could be created instead of GaN thin films. 15 Finally, substrates other than sapphire substrate could be employed for non-polar GaN growth. These substrates include silicon carbide, gallium nitride, silicon, zin c oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, and lithium gallate. In summary, the present invention describes the growth of non-polar (11 2 0) a-plane 20 GaN thin films on r-plane (1 1 02) sapphire substrates by employing a low temperature nucleation layer as a buffer layer prior to a high temperature growth of the epitaxial (1 120) a-plane GaN films. The epitaxial relationship is [0001]GaN 1[01] sapphire and [1100] GaN [11 20] sapphire with the positive GaN c-axis pointing in the same direction as the sapphire c- axis projection on the growth surface. 25 The foregoing description of one or more embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. 30 12 Claims What is claimed is:
canceled
canceled
canceled
Materials described outside the worked examples.
non-polar a-plane GaN
GaN
r-plane sapphire substrate
Al₂O₃
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Threading Dislocation Density | 26000000000 cm⁻² | GaN |
Stacking Fault Density | 380000 cm⁻¹ |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 9,039,834Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a flowchart that illustrates the steps of the MOC V D process for the growth of non-polar (11 2 0) a-plane GaN thin films on (1 1 20) r-plane sapphire, …
FIG. 2(c) is a schematic illustration of the epitaxial relationship between the GaN and r-plane sapphire;
FIGS. 3(a) and 3(b) are cross-sectional and plan-view transmission electron microscopy (TEM) images, respectively, of the defect structure of the a-plane GaN …
FIGS. 4(a) and 4(b) are atomic force microscopy (AFM) amplitude and height 5 images, respectively, of the surface of the as-grown a-plane GaN films.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
I. P. Smorchkova, C. R. Elsass, J. P. Ibbetson, R. Vetury, B. Heying, P. Fini, E. Haus, S. P. DenBaars, J. S. Speck, and U. K. Mishra, J. Appl. Phys. 86, 4520 (1999).
The method of claim 1, wherein the growth conditions and the substrate obtain the non-polar a-plane GaN film [[has]] having no c-plane content. currently amended
The method of claim 1, wherein the stacking fault density is at the top surface. previously presented
The method of claim 1, wherein the growth conditions obtain the non-polar a-plane GaN film with a stable a-plane orientation.
The method of claim 1, wherein the non-polar a-plane GaN film includes a thickness of 1.5 micrometers.
The method of claim 1, wherein growing the non-polar a-plane GaN film includes using 30 mol per minute Ga flow and 40,000 p mol per minute N flow, thereby providing a V/III ratio of approximately 1300. -4- G&C 30794.100- U S-C₁ SVG 13151491.04-15-2015.I₈J₉Y₉W₉PXXIFW3.CLM14214895.2.1227.3054.2214.3139.svg 0.283 3.29 Table Black and white 27.-28
O. Ambacher, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, W. J. Schaff, L. F. Eastman, R. Dimitrov, L. Wittmer, M. Stutzmann, W. Rieger, and J. 20 Hilsenbeck, J. Appl. Phys. 85, 3222 (1999).
I. Jin Seo, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, Phys. Rev. B 57, R₉₄₃₅ (1998).
R. Langer, J. Simon, V. Ortiz, N. T. Pelekanos, A. Barski, R. Andre, and M. Godlewski, Appl. Phys. Lett. 74, 3827 (1999). 25 5. P. Lefebvre, J. Allegre, B. Gil, H. Mathieu, N. Grandjean, M. Leroux, J. Massies, and P. Bigenwald, Phys. Rev. B 59, 15363 (1999).
P. Lefebvre, A. Morel, M. Gallart, T. Taliercio, J. Allegre, B. Gil, H. Mathieu, B. Damilano, N. Grandjean, and J. Massies, Appl. Phys. Lett. 78, 1252 (2001).
T. Takeuchi, C. Wetzel, S. Yamaguchi, H. Sakai, H. Amano, I. Akasaki, Y. 30 Kaneko, S. Nakagawa, Y. Yamaoka, and N. Yamada, Appl. Phys. Lett. 73, 1691 (1998).
P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, Nature (London 406, 865 (2000).
T. Sasaki and S. Zembutsu, J. App l e. Phys. 61, 2533 (1987).
C. J. Sun and M. Razeghi, App l. Phys. Lett. 63, 973 (1993). 5 11. T. Metzger, H. Angerer, O. Ambacher, M. Stutzmann, and E. Born, Phys. Status Solidi B 193, 391 (1996).
T. Lei, K. F. Ludwig, Jr., and T. D. Moustakas, J. App l e. Phys. 74, 4430 (1993).
C. R. Eddy, Jr., T. D. Moustakas, and J. Scanlon, J. App l e. Phys. 73, 448 10 (1993).
T. D. Moustakas, T. Lei, and R. J. Molnar, Physica B 185, 36 (1993).
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B. Heying, X. H. Wu, A. S. Keller, Y. Li, D. Kapolnek, B. P. Keller, S. P. DenBaars, and J. S. Speck, Appl. Phys. Lett. 68, 643 (1996). 20 Conclusion This concludes the description of the preferred embodiment of the present invention. The following describes some alternative embodiments for accomplishing the present invention. For example, as the inclusions in the description above indicate, there are many 25 modifications and variations of the MOCVD technique and equipment that could be used to grow non-polar (1120) a-plane GaN thin films on (1 1 02) r-plane sapphire substrates. Moreover, different growth conditions may be optimal for different MOCVD reactor designs. Many variations of this process are possible with the variety of reactor designs currently being using in industry and academia. Despite these differences, the growth parameters can 30 most likely be optimized to improve the quality of the films. The most important variables 11 for the MOCVD growth include growth temperature, V/III ratio, precursor flows, and growth pressure. In addition to the numerous modifications possible with the MOCVD growth technique, other modifications are possible. For example, the specific crystallographic 5 orientation of the r-plane sapphire substrate might be changed in order to optimize the subsequent epitaxial GaN growth. Further, r-plane sapphire substrates with a particular degree of miscut in a particular crystallographic direction might be optimal for growth. In addition, the nucleation layer deposition is crucial to achieving epitaxial GaN films with smooth growth surfaces and minimal crystalline defects. Other than optimizing the fundamental MOCVD parameters, use of A l N or AlGaN nucleation layers in place of GaN could prove useful in obtaining high quality a-plane GaN films. Further, although non-polar a-plan GaN thin films are described herein, the same techniques are applicable to non-polar m -plane GaN thin films. Moreover, non-polar InN, Al N, and A l InGaN thin films could be created instead of GaN thin films. 15 Finally, substrates other than sapphire substrate could be employed for non-polar GaN growth. These substrates include silicon carbide, gallium nitride, silicon, zin c oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, and lithium gallate. In summary, the present invention describes the growth of non-polar (11 2 0) a-plane 20 GaN thin films on r-plane (1 1 02) sapphire substrates by employing a low temperature nucleation layer as a buffer layer prior to a high temperature growth of the epitaxial (1 120) a-plane GaN films. The epitaxial relationship is [0001]GaN 1[01] sapphire and [1100] GaN [11 20] sapphire with the positive GaN c-axis pointing in the same direction as the sapphire c- axis projection on the growth surface. 25 The foregoing description of one or more embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. 30 12 Claims What is claimed is:
canceled
canceled
canceled
Materials described outside the worked examples.
non-polar a-plane GaN
GaN
r-plane sapphire substrate
Al₂O₃
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Threading Dislocation Density | 26000000000 cm⁻² | GaN |
Stacking Fault Density | 380000 cm⁻¹ |
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