METHOD AND SYSTEM FOR FABRICATING EDGE TERMINATION STRUCTURES IN GaN MATERIALS

Donald R. Disney

Patent

Atlas literature

Patent

US 8,741,707

METHOD AND SYSTEM FOR FABRICATING EDGE TERMINATION STRUCTURES IN GaN MATERIALS

Donald R. Disney, Isik C. Kizilyalli, Linda Romano, Andrew Edwards et al.

2014-06-03·US

Claims

Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.

3 independent · 25 dependent

1
IndependentGaNGaNinsulating region in GaN epitaxial layeredge termination structure (GaN, method claims 1-11)
A method for fabricating an edge termination structure, the method comprising: providing a GaN substrate of a ﬁrst conductivity type, the GaN substrate having a ﬁrst surface and a second surface, the ﬁrst surface opposite the second surface in a vertical dimension; forming a ﬁrst GaN epitaxial layer of the ﬁrst conductivity type coupled to the ﬁrst surface of the GaN substrate; and forming an insulating region in a ﬁrst portion of the ﬁrst GaN epitaxial layer, wherein the insulating region extends vertically through at least 90 % of the ﬁrst GaN epitaxial layer to separate an active device region of the ﬁrst GaN epitaxial layer from an outer region of the ﬁrst GaN epitaxial layer; wherein the insulating region circumscribes the active device region.
1. 2
  Dependent← claim 1GaNGaNinsulating region in GaN epitaxial layeredge termination structure (GaN, method claims 1-11)
  The method of claim 1 wherein the insulating region extends vertically through the ﬁrst GaN epitaxial layer and into the GaN substrate.
2. 3
  Dependent← claim 1GaNGaNinsulating region in GaN epitaxial layerGaNedge termination structure (GaN, method claims 1-11)
  The method of claim 1 further comprising: forming a second GaN epitaxial layer of a second conductivity type opposite the ﬁrst conductivity type, the second GaN epitaxial layer being coupled to the ﬁrst GaN epitaxial layer; wherein the insulating region also extends vertically through the second GaN epitaxial layer.
3. 6
  Dependent← claim 1GaNinsulating region in GaN epitaxial layeredge termination structure (GaN, method claims 1-11)
  The method of claim 1 wherein forming the insulating region comprises a plurality of ion implantations into the ﬁrst GaN epitaxial layer, each ion implantation step being performed at a diﬀerent energy such that corresponding implanted proﬁles overlap vertically to form a substantially continuous implanted region.
4. 7
  Dependent← claim 1GaNinsulating region in GaN epitaxial layeredge termination structure (GaN, method claims 1-11)
  The method of claim 1 wherein forming the insulating region comprises: etching a trench in the vertically into the ﬁrst GaN epitaxial layer, and ﬁlling the trench with an insulating material. withdrawn
5. 10
  Dependent← claim 1GaNedge termination structure (GaN, method claims 1-11)
  The method of claim 1 further comprising forming a metallic structure electrically coupled to a second portion of the ﬁrst GaN epitaxial layer, wherein the metallic structure comprises a Schottky contact to the second portion of the ﬁrst GaN epitaxial layer.
6. 11
  Dependent← claim 1GaNedge termination structure (GaN, method claims 1-11)
  The method of claim 1 further comprising forming a metallic structure electrically coupled to the second surface of the GaN substrate.
12
IndependentIII-nitride substrate (first conductivity type)first III-nitride epitaxial layer (first conductivity type)insulating region in III-nitride epitaxial layervertical power device structure (III-nitride, method claims 12-18)
A method of fabricating a vertical power device structure, the method comprising: forming an epitaxial structure by: providing a I II -nitride substrate of a ﬁrst conductivity type characterized by a ﬁrst dopant concentration; and forming a ﬁrst I II -nitride epitaxial layer of the ﬁrst conductivity type having a thickness and coupled to a ﬁrst surface of the I II -nitride substrate; deﬁning regions of the epitaxial structure by forming an insulating region of the epitaxial structure, wherein the insulating region electrically separates a device region of the epitaxial structure from an outer region of the epitaxial structure; and forming one or more active devices using at least the device region of the epitaxial structure, wherein the insulating region extends vertically through at least 90 % of the thickness of the ﬁrst I II -nitride epitaxial layer.
1. 13
  Dependent← claim 12first III-nitride epitaxial layer (first conductivity type)vertical power device structure (III-nitride, method claims 12-18)
  The method of claim 12 further comprising forming a Schottky metallic structure coupled to the ﬁrst I II -nitride epitaxial layer.
2. 14
  Dependent← claim 12first III-nitride epitaxial layer (first conductivity type)second III-nitride epitaxial layer (second conductivity type)vertical power device structure (III-nitride, method claims 12-18)
  The method of claim 12 further comprising: forming a second I II -nitride epitaxial layer of a second conductivity type coupled to the ﬁrst I II -nitride epitaxial layer; and forming an Ohmic metallic structure coupled to the second I II -nitride epitaxial layer
3. 15
  Dependent← claim 12III-nitride substrate (first conductivity type)vertical power device structure (III-nitride, method claims 12-18)
  The method of claim 12 further comprising forming an Ohmic metallic structure coupled to a second surface of the I II -nitride substrate.
4. 16
  Dependent← claim 12vertical power device structure (III-nitride, method claims 12-18)
  The method of claim 12 wherein the insulating region circumscribes the one or more active devices.
5. 17
  Dependent← claim 12first III-nitride epitaxial layer (first conductivity type)vertical power device structure (III-nitride, method claims 12-18)
  The method of claim 12 wherein the ﬁrst I II -nitride epitaxial layer is characterized by a second dopant concentration less than the ﬁrst dopant concentration.
6. 18
  Dependent← claim 12first III-nitride epitaxial layer (first conductivity type)insulating region in III-nitride epitaxial layervertical power device structure (III-nitride, method claims 12-18)
  The method of claim 12 wherein forming the insulating region comprises: Page 4 of 8 App l e. No. 13/335,383 PATENT Amdt. dated Response to Restriction Requirement of etching a trench vertically into the ﬁrst I II -nitride epitaxial layer; and ﬁlling the trench with an insulating material. withdrawn
19
IndependentGaNGaNinsulating region in GaN epitaxial layersemiconductor structure with edge termination (GaN, claims 19-28)
A semiconductor structure comprising: a GaN substrate having a ﬁrst surface and a second surface opposing the ﬁrst surface, wherein the GaN substrate is characterized by a ﬁrst conductivity type and a ﬁrst dopant concentration; a ﬁrst GaN epitaxial layer of the ﬁrst conductivity type coupled to the second surface of the GaN substrate, wherein the ﬁrst GaN epitaxial layer comprises: an active device region; an outer region; and an insulating region disposed between the active device region and the outer region, the insulating region having a thickness greater than 90 % of a thickness of the ﬁrst GaN epitaxial layer.
1. 20
  Dependent← claim 19GaNsemiconductor structure with edge termination (GaN, claims 19-28)
  The semiconductor structure of claim 19 further comprising a second GaN epitaxial layer of a second conductivity type coupled to the ﬁrst GaN epitaxial layer.
2. 22
  Dependent← claim 19GaNsemiconductor structure with edge termination (GaN, claims 19-28)vertical Schottky diode (GaN)
  The semiconductor structure of claim 19 wherein the active device region comprises a Schottky contact electrically coupled to a portion of the ﬁrst GaN epitaxial layer.
3. 24
  Dependent← claim 19semiconductor structure with edge termination (GaN, claims 19-28)vertical JFET (GaN)
  The semiconductor structure of claim 19 wherein the active device region includes one or more elements of a vertical JFET.
4. 25
  Dependent← claim 19semiconductor structure with edge termination (GaN, claims 19-28)vertical Schottky diode (GaN)
  The semiconductor structure of claim 19 wherein the active device region includes at least a portion of a vertical Schottky diode.
5. 26
  Dependent← claim 19semiconductor structure with edge termination (GaN, claims 19-28)
  The semiconductor structure of claim 19 further comprising a ﬁeld plate coupled to the active device region, the ﬁeld plate extending laterally over at least a portion of the insulating region.
6. 27
  Dependent← claim 19semiconductor structure with edge termination (GaN, claims 19-28)
  The semiconductor structure of claim 19 wherein the insulating region circumscribes the active device region.
7. 28
  Dependent← claim 19semiconductor structure with edge termination (GaN, claims 19-28)
  The semiconductor structure of claim 19 wherein: a depletion region is formed adjacent to the insulating region when the semiconductor structure is reverse biased; and a thickness of the depletion region is less than the thickness of the insulating region.

Device structures

Layer stacks claimed or described, ordered top of device to substrate.

edge termination structure (GaN, method claims 1-11)

insulating region in GaN epitaxial layerinsulating region

GaNdrift layer

GaNsubstrate

vertical power device structure (III-nitride, method claims 12-18)

insulating region in III-nitride epitaxial layerinsulating region

first III-nitride epitaxial layer (first conductivity type)drift layer

Materials

Materials described outside the worked examples.

GaN substrate (first conductivity type)

GaN

Substrate

Epitaxial Layer

insulating region in GaN epitaxial layer

Insulating Region

Why these are connected

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METHOD AND SYSTEM FOR FABRICATING EDGE TERMINATION STRUCTURES IN GaN MATERIALS | Matter42 Literature