A method of preparing a high-linearity GaN-based millimeter wave device, comprising: S1, growing anAlGaN/GaN heterojunction epitaxial layer on a substrate and directly growing a first p-type GaN region on the AlGaN/GaN heterojunction epitaxial layer, wherein a thickness of the first p-type GaN region is between 5 nm and 100 nm; S2, covering a region except a second p-type GaN region with a first photoresist, wherein a region not being covered by the first photoresist has a length between 10 nm and 100 nm and a width greater than 5 µm, and the region is etched to a AlGaN layer of the AlGaN/GaN heterojunction epitaxial layer by a dry etching process; performing a secondary epitaxial growth, wherein a thickness of the second p-type GaN region is equal to a length of the first p-type GaN region in step S1, and a doping concentration of the second p-type GaN B₂ region is greater than a doping concentration of the first p-type GaN region in step S1; and smoothing a device surface using a chemical mechanical polishing tech-nique; S3, defining a position of an active region by a second photoresist on an upper surface of the AlGaN/GaN heterojunction epitaxial layer and covering the active region; and etching an upper surface of theAlGaN/GaN heterojunction epitaxial layer in a non-active region by plasma bombardment with an etching depth of 200 nm⁻⁶⁰⁰ nm; S4, defining positions and patterns of a source electrode and a drain electrode using a third photoresist so that the positions of the source electrode and the drain electrode are at two ends of an upper surface of the active region; front and rear edges of the source elec-trode and the drain electrode coinciding with front and rear edges of the active region; regions of non-source electrode and non-drain electrode being covered with the third photoresist, first etching the regions to a surface of the AlGaN layer or over-etching the AlGaN layer within 3 nm using a dry etching method, then forming the source electrode and the drain electrode by using an electron beam evaporation or magnetron sput-tering method and a stripping process, and annealing in nitrogen atmosphere at a temperature above 800° C., so that the source electrode and the drain electrode form ohmic contacts with the AlGaN/GaN heterojunction epitaxial layer; and S5, defining a position and a pattern of the gate electrode using a fourth photoresist, the gate electrode having a length equal to the length of the second p-type GaN region in step S₂ and disposed directly above the first p-type GaN region and the second p-type GaN region; forming the gate electrode by using an electron beam evaporation or magnetron sputtering method and a stripping process; protecting the gate electrode, the source electrode and the drain electrode using a fifth photoresist, and etching places being not covered by the fifth photoresist to the AlGaN layer or the overetchingAlGaN layer within 3 nm by using a dry etching process; removing the fifth photoresist after the etching to complete the preparation of the high-linearity GaN-based millimeter wave device.

A method of preparing a high-linearity GaN-based millimeter wave device, comprising: S1, growing anAlGaN/GaN heterojunction epitaxial layer on a substrate and directly growing a first p-type GaN region on the AlGaN/GaN heterojunction epitaxial layer, wherein a thickness of the first p-type GaN region is between 5 nm and 100 nm; S2, covering a region except a second p-type GaN region with a first photoresist, wherein a region not being covered by the first photoresist has a length between 10 nm and 100 nm and a width greater than 5 µm, and the region is etched to a AlGaN layer of the AlGaN/GaN heterojunction epitaxial layer by a dry etching process; performing a secondary epitaxial growth, wherein a thickness of the second p-type GaN region is equal to a length of the first p-type GaN region in step S1, and a doping concentration of the second p-type GaN B₂ region is greater than a doping concentration of the first p-type GaN region in step S1; and smoothing a device surface using a chemical mechanical polishing tech-nique; S3, defining a position of an active region by a second photoresist on an upper surface of the AlGaN/GaN heterojunction epitaxial layer and covering the active region; and etching an upper surface of theAlGaN/GaN heterojunction epitaxial layer in a non-active region by plasma bombardment with an etching depth of 200 nm⁻⁶⁰⁰ nm; S4, defining positions and patterns of a source electrode and a drain electrode using a third photoresist so that the positions of the source electrode and the drain electrode are at two ends of an upper surface of the active region; front and rear edges of the source elec-trode and the drain electrode coinciding with front and rear edges of the active region; regions of non-source electrode and non-drain electrode being covered with the third photoresist, first etching the regions to a surface of the AlGaN layer or over-etching the AlGaN layer within 3 nm using a dry etching method, then forming the source electrode and the drain electrode by using an electron beam evaporation or magnetron sput-tering method and a stripping process, and annealing in nitrogen atmosphere at a temperature above 800° C., so that the source electrode and the drain electrode form ohmic contacts with the AlGaN/GaN heterojunction epitaxial layer; and S5, defining a position and a pattern of the gate electrode using a fourth photoresist, the gate electrode having a length equal to the length of the second p-type GaN region in step S₂ and disposed directly above the first p-type GaN region and the second p-type GaN region; forming the gate electrode by using an electron beam evaporation or magnetron sputtering method and a stripping process; protecting the gate electrode, the source electrode and the drain electrode using a fifth photoresist, and etching places being not covered by the fifth photoresist to the AlGaN layer or the overetchingAlGaN layer within 3 nm by using a dry etching process; removing the fifth photoresist after the etching to complete the preparation of the high-linearity GaN-based millimeter wave device.

A method of preparing a high-linearity GaN-based millimeter wave device, comprising: S1, growing anAlGaN/GaN heterojunction epitaxial layer on a substrate and directly growing a first p-type GaN region on the AlGaN/GaN heterojunction epitaxial layer, wherein a thickness of the first p-type GaN region is between 5 nm and 100 nm; S2, covering a region except a second p-type GaN region with a first photoresist, wherein a region not being covered by the first photoresist has a length between 10 nm and 100 nm and a width greater than 5 µm, and the region is etched to a AlGaN layer of the AlGaN/GaN heterojunction epitaxial layer by a dry etching process; performing a secondary epitaxial growth, wherein a thickness of the second p-type GaN region is equal to a length of the first p-type GaN region in step S1, and a doping concentration of the second p-type GaN B₂ region is greater than a doping concentration of the first p-type GaN region in step S1; and smoothing a device surface using a chemical mechanical polishing tech-nique; S3, defining a position of an active region by a second photoresist on an upper surface of the AlGaN/GaN heterojunction epitaxial layer and covering the active region; and etching an upper surface of theAlGaN/GaN heterojunction epitaxial layer in a non-active region by plasma bombardment with an etching depth of 200 nm⁻⁶⁰⁰ nm; S4, defining positions and patterns of a source electrode and a drain electrode using a third photoresist so that the positions of the source electrode and the drain electrode are at two ends of an upper surface of the active region; front and rear edges of the source elec-trode and the drain electrode coinciding with front and rear edges of the active region; regions of non-source electrode and non-drain electrode being covered with the third photoresist, first etching the regions to a surface of the AlGaN layer or over-etching the AlGaN layer within 3 nm using a dry etching method, then forming the source electrode and the drain electrode by using an electron beam evaporation or magnetron sput-tering method and a stripping process, and annealing in nitrogen atmosphere at a temperature above 800° C., so that the source electrode and the drain electrode form ohmic contacts with the AlGaN/GaN heterojunction epitaxial layer; and S5, defining a position and a pattern of the gate electrode using a fourth photoresist, the gate electrode having a length equal to the length of the second p-type GaN region in step S₂ and disposed directly above the first p-type GaN region and the second p-type GaN region; forming the gate electrode by using an electron beam evaporation or magnetron sputtering method and a stripping process; protecting the gate electrode, the source electrode and the drain electrode using a fifth photoresist, and etching places being not covered by the fifth photoresist to the AlGaN layer or the overetchingAlGaN layer within 3 nm by using a dry etching process; removing the fifth photoresist after the etching to complete the preparation of the high-linearity GaN-based millimeter wave device.

A method of preparing a high-linearity GaN-based millimeter wave device, comprising: S1, growing anAlGaN/GaN heterojunction epitaxial layer on a substrate and directly growing a first p-type GaN region on the AlGaN/GaN heterojunction epitaxial layer, wherein a thickness of the first p-type GaN region is between 5 nm and 100 nm; S2, covering a region except a second p-type GaN region with a first photoresist, wherein a region not being covered by the first photoresist has a length between 10 nm and 100 nm and a width greater than 5 µm, and the region is etched to a AlGaN layer of the AlGaN/GaN heterojunction epitaxial layer by a dry etching process; performing a secondary epitaxial growth, wherein a thickness of the second p-type GaN region is equal to a length of the first p-type GaN region in step S1, and a doping concentration of the second p-type GaN B₂ region is greater than a doping concentration of the first p-type GaN region in step S1; and smoothing a device surface using a chemical mechanical polishing tech-nique; S3, defining a position of an active region by a second photoresist on an upper surface of the AlGaN/GaN heterojunction epitaxial layer and covering the active region; and etching an upper surface of theAlGaN/GaN heterojunction epitaxial layer in a non-active region by plasma bombardment with an etching depth of 200 nm⁻⁶⁰⁰ nm; S4, defining positions and patterns of a source electrode and a drain electrode using a third photoresist so that the positions of the source electrode and the drain electrode are at two ends of an upper surface of the active region; front and rear edges of the source elec-trode and the drain electrode coinciding with front and rear edges of the active region; regions of non-source electrode and non-drain electrode being covered with the third photoresist, first etching the regions to a surface of the AlGaN layer or over-etching the AlGaN layer within 3 nm using a dry etching method, then forming the source electrode and the drain electrode by using an electron beam evaporation or magnetron sput-tering method and a stripping process, and annealing in nitrogen atmosphere at a temperature above 800° C., so that the source electrode and the drain electrode form ohmic contacts with the AlGaN/GaN heterojunction epitaxial layer; and S5, defining a position and a pattern of the gate electrode using a fourth photoresist, the gate electrode having a length equal to the length of the second p-type GaN region in step S₂ and disposed directly above the first p-type GaN region and the second p-type GaN region; forming the gate electrode by using an electron beam evaporation or magnetron sputtering method and a stripping process; protecting the gate electrode, the source electrode and the drain electrode using a fifth photoresist, and etching places being not covered by the fifth photoresist to the AlGaN layer or the overetchingAlGaN layer within 3 nm by using a dry etching process; removing the fifth photoresist after the etching to complete the preparation of the high-linearity GaN-based millimeter wave device.