Date of Award

8-2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Electrical Engineering

Advisor

Harrell, William R

Committee Member

Poole , Kelvin F

Committee Member

Bridgwood , Michael A

Abstract

Copper Schottky contacts to n-type 4H Silicon Carbide with nickel ohmic contacts were fabricated. The electrical and physical characteristics of these Schottky diodes were analyzed and the results are presented. I-V measurements revealed two sets of characteristics, one indicating nearly ideal Schottky behavior and the other exhibiting regions with two barrier heights. The reason for this observed phenomenon was studied and attributed to the in-homogeneity of the Silicon Carbide surface. The I-V and C-V characteristics were used to extract the electrical parameters, which include barrier height, ideality factor, reverse saturation current density, and doping concentration. The measured barrier height was close to the Schottky-Mott limit. The importance of an additional surface clean prior to the deposition of the Schottky contacts was established. Significant improvement in the electrical characteristics was observed when this second surface clean was performed. C-V measurements and XPS results indicate that this improvement was due to the removal of an oxide layer from the SiC surface which formed some time after the initial wafer clean. This thesis presents some of the first experimental data on Cu/4H-SiC Schottky diodes.

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