Method of fabricating self-aligned silicon carbide semiconductor devices
View Patent ↗Methods of constructing silicon carbide semiconductor devices in a self-aligned manner. According to one aspect of the invention, the method may include forming a mesa structure in a multi-layer laminate including at least a first and second layer of silicon carbide material. The mesa structure may then be utilized in combination with at least one planarization step to construct devices in a self-aligned manner. According to another aspect of the present invention, the mesa structure may be formed subsequent to an ion implantation and anneal steps to construct devices in a self-aligned manner. According to another aspect of the present invention, a high temperature mask capable of withstanding the high temperatures of the anneal process may be utilized to form devices in a self-aligned manner.
1. A Silicon-Carbide (SiC) device, comprising:
a mesa structure;
a sidewall on said mesa structure; and
a base contact metal;
wherein a lower end of said sidewall is in substantially the same plane as a lower boundary of said base contact metal;
wherein an upper end of said sidewall is at a plane above an upper boundary of said base contact metal.
2. The device of claim 1 , further including an emitter contact metal on said mesa structure;
wherein said emitter contact metal includes a top surface, a bottom surface and a lateral surface extending between said top and bottom surfaces of said emitter contact metal; and
wherein said base contact metal includes a top surface, a bottom surface and a lateral surface extending between said top and bottom surfaces of said base contact metal;
wherein said lateral surface of said emitter contact metal extended downward is substantially aligned with said lateral surface of said base contact metal.
3. The device of claim 1 , further including a transition between regions of differing doping density substantially defined by a transition surface, said transition surface being substantially aligned with a surface of said sidewall.
4. The device of claim 1 , further including an area of contact between said sidewall and a metal contact.
5. The device of claim 1 , wherein said upper end of said sidewall is at a plane lower than an upper end of said the emitter mesa.
6. The device of claim 1 , wherein said sidewall comprises a material capable of withstanding 1800 C in a silane atmosphere.
7. The device of claim 3 , wherein said surface of said sidewall is an outer surface of said sidewall.
8. The device of claim 3 , wherein said surface of said sidewall is an inner surface of said sidewall.
9. The device of claim 3 , wherein said transition surface and said surface of said sidewall meet a substantially horizontal surface.
10. The device of claim 9 , wherein said transition surface, said surface of said sidewall and said horizontal surface collectively and at least partially bound a base contact metal, a base contact and a base.
11. The device of claim 9 , wherein said transition surface, said surface of said sidewall and said horizontal surface collectively and at least partially bound an emitter mesa, a base and a base contact.
12. The device of claim 4 , wherein said area of contact is proximate to an area of the upper surface of a metal contact said upper surface having a first surface patterning at a first area thereof and a second surface patterning, different that said first surface patterning at a second area thereof, wherein said first area is closer to said sidewall than is said second area.
13. The device of claim 12 , wherein a difference of surface patterning as between said first and second areas relates to pitting, mouse bites or etching artifacts.
14. The device of claim 6 , wherein said material is one of: carbon, Al203, AlN, BN, tungsten and diamond.
15. A Silicon-Carbide (SiC) device, comprising:
a mesa structure;
a sidewall on said mesa structure;
an emitter contact metal on said mesa structure;
wherein said emitter contact metal includes a top surface, a bottom surface and a lateral surface extending between said top and bottom surfaces of said emitter contact metal; and
a base contact metal;
wherein said base contact metal includes a top surface, a bottom surface and a lateral surface extending between said top and bottom surfaces of said base contact metal;
wherein said lateral surface of said emitter contact metal extended downward is substantially aligned with said lateral surface of said base contact metal.
16. The device in claim 15 , wherein a lower end of said sidewall is in substantially the same plane as a lower boundary of said base contact metal;
wherein an upper end of said sidewall is at a plane above an upper boundary of said base contact metal.
17. The device in claim 15 , further including a transition between regions of differing doping density substantially defined by a transition surface, said transition surface being substantially aligned with a surface of said sidewall.
18. The device of claim 15 , further including an area of contact between said sidewall and a metal contact.
19. The device of claim 17 , wherein said surface of said sidewall is an outer surface of said sidewall.
20. The device of claim 17 , wherein said surface of said sidewall is an inner surface of said sidewall.
21. The device of claim 17 , wherein said transition surface and said surface of said sidewall meet a substantially horizontal surface.
22. The device of claim 21 , wherein said transition surface, said surface of said sidewall and said horizontal surface collectively and at least partially bound a base contact metal, a base contact and a base.
23. The device of claim 21 , wherein said transition surface, said surface of said sidewall and said horizontal surface collectively and at least partially bound an emitter mesa, a base and a base contact.
24. The device of claim 18 , wherein said area of contact is proximate to an area of the upper surface of a metal contact said upper surface having a first surface patterning at a first area thereof and a second surface patterning, different that said first surface patterning at a second area thereof, wherein said first area is closer to said sidewall than is said second area.
25. The device of claim 24 , wherein a difference of surface patterning as between said first and second areas relates to pitting, mouse bites or etching artifacts.