Micropipe-free silicon carbide and related method of manufacture
View Patent ↗Micropipe-free, single crystal, silicon carbide (SiC) and related methods of manufacture are disclosed. The SiC is grown by placing a source material and seed material on a seed holder in a reaction crucible of the sublimation system, wherein constituent components of the sublimation system including the source material, reaction crucible, and seed holder are substantially free from unintentional impurities. By controlling growth temperature, growth pressure, SiC sublimation flux and composition, and a temperature gradient between the source material and the seed material or the SiC crystal growing on the seed material during the PVT process, micropipe-inducing process instabilities are eliminated and micropipe-free SiC crystal is grown on the seed material.
1. A micropipe-free silicon carbide (SiC) wafer having a minimum diameter selected from a group of diameters consisting of at least 2 inches, at least 3 inches, and at least 100 mm, sliced from a SiC crystal grown in the nominal c-axis direction by a process of placing a source material and a seed material in a reaction crucible of a sublimation system, wherein constituent components of the sublimation system including at least the source material and the reaction crucible are substantially free from unintentional impurities, and controlling growth temperature, growth pressure, SiC sublimation flux and composition, and a temperature gradient between the source material and the seed material or a SiC crystal growing on the seed material during a physical vapor transport (PVT) process to eliminate micropipe-inducing process instabilities wherein the micropipe-free silicon carbide (SiC) wafer has a micropipe density of zero.
2. A micropipe-free silicon carbide (SiC) wafer having a minimum diameter of 100 mm to 125 mm sliced from a SiC crystal grown in the nominal c-axis direction by a process of placing a source material and a seed material in a reaction crucible of a sublimation system, wherein constituent components of the sublimation system including at least the source material and the reaction crucible are substantially free from unintentional impurities, and controlling growth temperature, growth pressure, SiC sublimation flux and composition, and a temperature gradient between the source material and the seed material or a SiC crystal growing on the seed material during a physical vapor transport (PVT) process to eliminate micropipe-inducing process instabilities wherein the micropipe-free silicon carbide (SiC) wafer has a micropipe density of zero.
3. The micropipe-free SiC wafer of claim 2 , comprising a homo-epitaxial SiC layer formed on a principal surface of the wafer.
4. The micropipe-free SiC wafer of claim 2 , comprising a hetero-epitaxial Group III-nitride layer formed on a principal surface of the wafer.
5. The micropipe-free SiC wafer of claim 4 , wherein the Group III-nitride layer comprises at least one selected from a group consisting of GaN, AlGaN, AN, AlInGaN, InN, and AlInN.
6. A micropipe-free silicon carbide (SiC) wafer having a minimum diameter of at least 100 mm to 150 mm sliced from a SiC crystal grown in the nominal c-axis direction by a process of placing a source material and a seed material in a reaction crucible of a sublimation system, wherein constituent components of the sublimation system including at least the source material and the reaction crucible are substantially free from unintentional impurities, and controlling growth temperature, growth pressure, SiC sublimation flux and composition, and a temperature gradient between the source material and the seed material or a SiC crystal growing on the seed material during a physical vapor transport (PVT) process to eliminate micropipe-inducing process instabilities wherein the micropipe-free silicon carbide (SiC) wafer has a micropipe density of zero.
7. The micropipe-free SiC wafer of claim 6 comprising a homo-epitaxial layer formed on a principal surface of the wafer.
8. The micropipe-free SiC wafer of claim 7 , wherein the homo-epitaxial layer is SiC.
9. The micropipe-free SiC wafer of claim 6 comprising a hetero-epitaxial layer formed on a principal surface of the wafer.
10. The micropipe-free SiC wafer of claim 9 , wherein the hetero-epitaxial layer is a Group III-nitride layer.
11. The micropipe-free SiC wafer of claim 10 , wherein the Group III-nitride layer comprises at least one selected from a group consisting of GaN, AlGaN, AlN, AlInGaN, InN, and AlInN.
12. The micropipe-free SiC wafer of claim 6 , having a polytype selected from a group of polytypes consisting of 3C, 4H, 6H, and 15R.
13. The micropipe-free SiC wafer of claim 6 comprising a homo-epitaxial SiC layer formed on a principal surface of the wafer.
14. The micropipe-free SiC wafer of claim 6 comprising a hetero-epitaxial Group III-nitride layer formed on a principal surface of the wafer.
15. The micropipe-free SiC wafer of claim 14 , wherein the Group III-nitride layer comprises at least one selected from a group consisting of GaN, AlGaN, AN, AlInGaN, InN, and AlInN.
16. The micropipe-free SiC wafer of claim 6 , wherein the SiC wafer comprises opposing first and second surfaces, an epitaxial layer on at least the first surface of the SiC wafer and a concentration of dopant atoms defining a conductivity for the epitaxial layer; and a semiconductor device comprising source/drain regions in the epitaxial layer and defining a channel region in the epitaxial layer.
17. The micropipe-free SiC wafer of claim 16 , further comprising: a gate dielectric layer formed on the channel region; and a metal gate structure formed on the gate dielectric layer over the channel region.
18. The micropipe-free SiC wafer of claim 16 , wherein the semiconductor device comprises at least one of a junction field-effect transistor and a hetero-field effect transistor.
19. The micropipe-free SiC wafer of claim 6 , wherein the SiC wafer comprises opposing first and second surfaces, an epitaxial layer formed on at least the first surface, and a concentration of dopant atoms defining a conductivity for the epitaxial layer; and a semiconductor device formed at least in part in the epitaxial layer.
20. The micropipe-free SiC wafer of claim 19 , wherein the semiconductor device comprises at least one of a Schottky barrier diode, a junction barrier Schottky diode, a thyristor, a bipolar junction transistor, and a PiN diode.
21. The micropipe-free SiC wafer of claim 6 , wherein the SiC wafer comprises opposing first and second surfaces, an epitaxial layer on at least the first surface of the SiC wafer and a concentration of dopant atoms defining a conductivity for the epitaxial layer; and a semiconductor device comprising source/drain regions in the epitaxial layer and defining a channel region in the epitaxial layer.
22. The micropipe-free SiC wafer of claim 21 , further comprising: a gate dielectric layer formed on the channel region; and a metal gate structure formed on the gate dielectric layer over the channel region.
23. The micropipe-free SiC wafer of claim 21 , wherein the semiconductor device comprises at least one of a junction field-effect transistor and a hetero-field effect transistor.
24. The micropipe-free SiC wafer of claim 6 , wherein the SiC wafer comprises opposing first and second surfaces, an epitaxial layer formed on at least the first surface, and a concentration of dopant atoms defining a conductivity for the epitaxial layer; and a semiconductor device formed at least in part in the epitaxial layer.
25. The micropipe-free SiC wafer of claim 24 , wherein the semiconductor device comprises at least one of a Schottky barrier diode, a junction barrier Schottky diode, a thyristor, a bipolar junction transistor, and a PiN diode.