Electron cyclotron resonance plasma etching of n-SiC and evaluation of Ni/n-SiC contacts by current noise measurements

The Si surface of n-SiC is etched by an Ar electron cyclotron resonance pla sma in order to smooth the as-received substrates. Low-frequency current no ise characteristics of Ohmic contacts of the wide-band-gap semiconductor n- SiC are investigated, Ohmic contacts with a diameter of 200 mum have a mini mum Ohmic contact resistance of the order of 10(-4) Omega .cm(2) at an allo ying temperature of 1000 degreesC for 30 min. These low resistance Ohmic co ntacts show typical 1/f current noise characteristics that increase with th e square of the sample current I-2. A sample with a higher contact resistan ce exhibits, however, current noise power increase with increasing sample c urrent I. The relevant total electron number between the electrodes ofthe b ulk substrate is estimated from the resistance and by finite element method simulation, from which the Hooge parameter alpha (H) is estimated to be ap proximately 40.