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 plasma in order to smooth the as-received substrates. Low-frequency current noise characteristics of Ohmic contacts of the wide-band-gap semiconductor n-SiC are investigated, Ohmic contacts with a diameter of 200 mum have a minimum Ohmic contact resistance of the order of 10(-4) Omega .cm(2) at an alloying temperature of 1000 degreesC for 30 min. These low resistance Ohmic contacts show typical 1/f current noise characteristics that increase with the square of the sample current I-2. A sample with a higher contact resistance exhibits, however, current noise power increase with increasing sample current I. The relevant total electron number between the electrodes ofthe bulk substrate is estimated from the resistance and by finite element method simulation, from which the Hooge parameter alpha (H) is estimated to be approximately 40.