Silicon carbide transistor and method
AssigneeMotorola, Inc.
InventorsCharles E. Weitzel, Karen E. Moore, Kenneth L. Davis
Life of this patent
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Abstract
A silicon carbide MESFET (10) is formed to have a source (21) and a drain (22) that are self-aligned to a gate (16) of the MESFET (10). The gate (16) is formed to have a T-shaped structure with a gate-to-source spacer (18) and gate-to-drain spacer (19) along each side of a base of the gate (16). The gate (16) is used as a mask for implanting dopants to form the source (21) and drain (22). A laser annealing is performed after the implantation to activate the dopants. Because the laser annealing is a low temperature operation, the gate (16) is not detrimentally affected during the annealing.
Claims18
A method of forming a silicon carbide transistor comprising:
- forming a gate having a gate-to-source dielectric spacer along a first edge of the gate wherein the gate is on a silicon carbide substrate;
- positioning a dopant within the substrate;
- and
- activating the dopant.
A method of forming a silicon carbide MESFET comprising:
- providing a silicon carbide substrate having a surface;
- forming a dielectric layer on the surface of the substrate, the dielectric layer having a surface;
- opening a gate footprint opening through the dielectric layer and exposing a first portion of the surface of the substrate;
- forming a gate having a cross-member on the surface of the dielectric layer and a base portion that is in the gate footprint opening and on the first portion of the surface of the substrate;
- positioning a dopant within the substrate to form a source wherein an edge of the source substantially aligns with a first edge of the cross-member;
- and
- activating the dopant at an ambient temperature of less than approximately 600.degree. Celsius.
Dependencies are inferred from the claim text.