The Effect of Plasma Etching on the Electrical Characteristics of 4H-SiC Schottky Diodes

摘要

Sputtered nickel Ohmic contacts have been successfully produced on 4H-S1C substrates. The (Ohmic) contact resistances are seen to improve from R_C=2.7x10~9Ω, to R_C=4-56Ω after annealing at 1000℃ in N_2 atmosphere. Schottky diodes were produced on the silicon carbide (SiC) surface after etching in an SF_6/O_2 inductively coupled plasma (ICP) for 3 minutes at varying substrate bias voltages. The ideality factors of all diodes formed onto the etched surfaces increased in comparison to the control sample. The highest ideality factor was observed for the diodes produced after etching at -0V and -245V bias voltage. A two diode and resistor model was applied to the results which successfully accounted for the excess leakage paths.