US 12,439,664 B2
Methods of forming ohmic contacts on semiconductor devices with trench/mesa structures
Madankumar Sampath, Morrisville, NC (US); Sei-Hyung Ryu, Cary, NC (US); and Rahul R. Potera, Apex, NC (US)
Assigned to Wolfspeed, Inc., Durham, NC (US)
Filed by Wolfspeed, Inc., Durham, NC (US)
Filed on Jun. 24, 2022, as Appl. No. 17/848,907.
Prior Publication US 2023/0420536 A1, Dec. 28, 2023
Int. Cl. H10D 62/832 (2025.01); H01L 21/285 (2006.01); H10D 62/85 (2025.01); H10D 64/62 (2025.01)
CPC H10D 62/85 (2025.01) [H01L 21/28575 (2013.01); H10D 62/8325 (2025.01); H10D 64/62 (2025.01)] 28 Claims
OG exemplary drawing
 
1. A method of forming ohmic contacts on a semiconductor structure having a trench and a mesa adjacent the trench, the method comprising:
forming a dielectric layer in the trench;
depositing a first metal on a top surface of the mesa;
removing the dielectric layer from the trench;
after removing the dielectric layer from the trench, annealing the structure at a first contact anneal temperature to form a first ohmic contact on the top surface of the mesa;
depositing a second metal on a bottom surface of the trench; and
annealing the structure at a second contact anneal temperature, less than the first contact anneal temperature to form a second ohmic contact to the bottom surface of the trench.