Methods of treating a silicon carbide substrate for improved epitaxial deposition and resulting structures and devices
View Patent ↗A method is disclosed for treating a silicon carbide substrate for improved epitaxial deposition thereon and for use as a precursor in the manufacture of devices such as light emitting diodes. The method includes the steps of implanting dopant atoms of a first conductivity type into the first surface of a conductive silicon carbide wafer having the same conductivity type as the implanting ions at one or more predetermined dopant concentrations and implant energies to form a dopant profile, annealing the implanted wafer, and growing an epitaxial layer on the implanted first surface of the wafer.
1. A method of performing epitaxial deposition comprising:
implanting dopant atoms of a first conductivity type into a first surface of a conductive silicon carbide substrate having the same conductivity type as the implanting ions at one or more predetermined dopant concentrations and implant energies to form an implanted dopant profile to a predetermined depth in the silicon carbide substrate;
annealing the implanted substrate; and
growing a Group III nitride epitaxial layer on the implanted first surface of the silicon carbide substrate;
wherein the implanted substrate is annealed in Argon at a temperature of 1300° C. for 90 minutes.
2. The method according to claim 1 wherein implanting dopant atoms comprises carrying out a plurality of implanting steps at varying doses and energy levels in order to produce a relatively flat implantation profile having predetermined depth.
3. The method according to claim 2 comprising implanting dopant atoms in the implant region to a peak concentration of implanted dopant atoms of between about 1E19 and 5E21 cm −3 .
4. The method according to claim 2 comprising implanting dopant atoms to a peak concentration of implanted dopant atoms of about 1E21 cm −3 and to a depth within the silicon carbide substrate of about 500 Angstroms.
5. The method according to claim 2 comprising implanting the silicon carbide substrate with phosphorus donor atoms at a first dopant concentration of 2E15 cm −2 and an implant energy of 25 keV and a second dopant concentration of 3.6E15 cm −2 at an implant energy of 50 key.
6. The method according to claim 1 comprising implanting dopant atoms selected from the group consisting of nitrogen and phosphorus into an n-type silicon carbide substrate.
7. The method according to claim 1 comprising implanting dopant atoms selected from the group consisting of boron and aluminum into a p-type silicon carbide substrate.
8. The method according to claim 1 , wherein an interfacial voltage between the substrate and the epitaxial layer is less than 700 mV.
9. The method according to claim 1 , wherein an interfacial voltage between the substrate and the epitaxial layer is less than 400 mV.
10. A method of forming a light emitting diode comprising:
implanting dopant atoms of a first conductivity type into the first surface of a conductive silicon carbide wafer having the same conductivity type as the implanting ions at one or more predetermined dopant concentrations and implant energies to form an implanted dopant profile having a predetermined depth in the silicon carbide wafer;
annealing the implanted wafer in Argon at a temperature of 1300° C. for 90 minutes;
forming a conductive buffer region on the implanted first surface of the silicon carbide wafer;
forming an active region on the conductive buffer region;
forming a first ohmic contact on said active region; and
forming a second ohmic contact on the opposite surface of said silicon carbide wafer.
11. The method according to claim 10 further comprising fabricating the active region as a single heterostructure.
12. The method according to claim 10 further comprising fabricating the active region as a double heterostructure.
13. The method according to claim 10 further comprising fabricating the active region as a single quantum well.
14. The method according to claim 10 further comprising fabricating the active region as a multiple quantum well.
15. The method according to claim 10 further comprising carrying out a plurality of implanting steps at varying doses and energy levels in order to produce a relatively flat implantation profile having a predetermined depth.
16. The method according to claim 15 further comprising implanting dopant atoms in the implant region to a peak concentration of implanted dopant atoms of between about 1E19 and 5E21 cm −3 .
17. The method according to claim 15 further comprising implanting dopant atoms in the implant region to a peak concentration of implanted dopant atoms of about 1E21 cm −3 and a thickness of about 500 Angstroms.
18. The method according to claim 10 further comprising implanting the silicon carbide wafer with phosphorus donor atoms at a first dopant concentration of 2E15 cm −2 and an implant energy of 25 keV and a second dopant concentration of 3.6E15 cm −2 at an implant energy of 50 keV.
19. The method according to claim 10 , wherein an interfacial voltage between the substrate and the conductive buffer region is less than 700 mV.
20. The method according to claim 10 , wherein an interfacial voltage between the substrate and the conductive buffer region is less than 400 mV.