Gallium nitride-based high electron mobility transistor epitaxial wafer with an InGaN/GaN cap layer comprising first sublayers doped with a main doping element and second sublayers doped with the first doping element and an auxiliary doping element, and preparation method therefor
The present application relates to the technical field of semiconductors, and provides a gallium nitride (GaN)-based high electron mobility transistor epitaxial wafer and a preparation method therefor. The GaN-based high electron mobility transistor epitaxial wafer comprises a substrate, and a buffer layer, a high-resistance buffer layer, a channel layer, an AlGaN barrier layer, and a cap layer which are stacked on the substrate; the cap layer comprises first sublayers and second sublayers which are grown alternately; the first sublayers are GaN layers; the second sublayers are InGaN layers; both the first sublayers and the second sublayers are doped with a main doping element; the main doping element is at least one of Be and Mg; the second sublayers are further doped with an auxiliary doping element; the auxiliary doping element is at least one of O, Mg, Si and Zn.
1 . A GaN-based high electron mobility transistor epitaxial wafer, comprising:
a substrate; and
a plurality of layers further including a buffer layer, a high-resistance buffer layer, a channel layer, an AlGaN barrier layer, and a cap layer, the plurality of layers being successively stacked on the substrate; wherein:
the cap layer comprises first sublayers and second sublayers, the first sublayers and the second sublayers being alternately arranged;
the first sublayers are GaN layers;
the second sublayers are InGaN layers, wherein a dopant concentration of In in the second sublayers ranges from 10 cm −3 to 104 cm −3 ;
both the first sublayers and the second sublayers are doped with a main doping element;
the main doping element is at least one of Be and Mg;
the second sublayers are further doped with an auxiliary doping element; and
the auxiliary doping element is at least one of O, Mg, Si and Zn.
2 . The GaN-based high electron mobility transistor epitaxial wafer of claim 1 , wherein dopant concentrations of the main doping element in the first sublayers and the second sublayers all range from 1*10 19 cm −3 to 9*10 21 cm −3 .
3 . The GaN-based high electron mobility transistor epitaxial wafer of claim 1 , wherein dopant concentrations of the auxiliary doping element in the second sublayers range from 1*10 18 cm −3 to 5*10 21 cm −3 .
4 . The GaN-based high electron mobility transistor epitaxial wafer of claim 1 , wherein a ratio of a dopant concentration of the main doping element to a dopant concentration of the auxiliary doping element in the second sublayers ranges from 1:1 to 5:1.
5 . The GaN-based high electron mobility transistor epitaxial wafer of claim 1 , wherein the cap layer comprises n periods of alternately grown first sublayers and second sublayers, 1≤n≤10.
6 . The GaN-based high electron mobility transistor epitaxial wafer of claim 1 , wherein a total thickness of the cap layer ranges from 50 nm to 150 nm.
7 . The GaN-based high electron mobility transistor epitaxial wafer of claim 6 , wherein a thickness of each of the first sublayers ranges from 5 nm to 20 nm, and a thickness of each of the second sublayers ranges from 10 nm to 30 nm.
8 . A method for preparing a GaN-based high electron mobility transistor epitaxial wafer, comprising:
providing a substrate; and
successively growing a buffer layer, a high-resistance buffer layer, a channel layer, an AlGaN barrier layer, and a cap layer on the substrate, wherein:
the cap layer comprises first sublayers and second sublayers which are grown alternately;
the first sublayers are GaN layers;
the second sublayers are InGaN layers wherein a dopant concentration of In in the second sublayers ranges from 10 cm −3 to 10 4 cm −3 ;
both the first sublayers and the second sublayers are doped with a main doping element;
the main doping element is at least one of Be and Mg;
the second sublayers are further doped with an auxiliary doping element; and
the auxiliary doping element is at least one of O, Mg, Si and Zn.
9 . The method of claim 8 , wherein the step of successively growing the buffer layer, the high-resistance buffer layer, the channel layer, the AlGaN barrier layer and the cap layer on the substrate further comprises:
growing the cap layer on the AlGaN barrier layer under conditions where a growth temperature ranges from 800° C. to 1050° C. and a growth pressure ranges from 50 torr to 600 torr.
10 . The method of claim 8 , further comprising:
performing furnace annealing for the GaN-based high electron mobility transistor epitaxial wafer after growing the cap layer.
11 . The method of claim 10 , wherein an annealing temperature ranges from 600° C. to 900° C. and an annealing time ranges from 5 min to 10 min.
12 . The method of claim 8 , wherein the cap layer comprises n periods of alternately grown first sublayers and second sublayers, 1≤n≤10.
13 . The method of claim 8 , wherein a thickness of each of the first sublayers ranges from 5 nm to 20 nm, and a thickness of each of the second sublayers ranges from 10 nm to 30 nm.
14 . An electronic device, comprising:
a substrate; and
a plurality of layers further including a buffer layer, a high-resistance buffer layer, a channel layer, an AlGaN barrier layer, and a cap layer, the plurality of layers being successively stacked on the substrate; wherein:
the cap layer comprises first sublayers and second sublayers, the first sublayers and the second sublayers being alternately arranged;
the first sublayers are GaN layers;
the second sublayers are InGaN layers, wherein a dopant concentration of In in the second sublayers ranges from 10 cm −3 to 10 4 cm −3 ;
both the first sublayers and the second sublayers are doped with a main doping element;
the main doping element is at least one of Be and Mg;
the second sublayers are further doped with an auxiliary doping element; and
the auxiliary doping element is at least one of O, Mg, Si and Zn.
15 . The electronic device of claim 14 , wherein dopant concentrations of the main doping element in the first sublayers and the second sublayers all range from 1*10 19 cm −3 to 9*10 21 cm −3 .
16 . The electronic device of claim 14 , wherein dopant concentrations of the auxiliary doping element in the second sublayers range from 1*10 18 cm −3 to 5*10 21 cm −3 .
17 . The electronic device of claim 14 , wherein a ratio of a dopant concentration of the main doping element to a dopant concentration of the auxiliary doping element in the second sublayers ranges from 1:1 to 5:1.
18 . The electronic device of claim 14 , wherein the cap layer comprises n periods of alternately grown first sublayers and second sublayers, 1≤n≤10.
19 . The electronic device of claim 14 , wherein a total thickness of the cap layer ranges from 50 nm to 150 nm.
20 . The electronic device of claim 19 , wherein a thickness of each of the first sublayers ranges from 5 nm to 20 nm, and a thickness of each of each of the second sublayers ranges from 10 nm to 30 nm.