Electrical characterizations of hydrogenated 4H-SiC epitaxial samples

Abstract

11th International Autumn Meeting on Gettering and Defect Engineering in Semiconductor Technology (GADEST 2005), Giens, FRANCE, SEP 25-30, 2005International audience4H-SiC epitaxial layers were hydrogenated by means of plasma treatment and annealing, aiming at passivating the surface by forming bonds with Si atoms. Ni/SiC Schottky contacts were processed, and investigated by electrical methods (I-V-T, C-V-T, EBIC, DLTS). The annealings were performed at two different temperatures (300 degrees C and 400 degrees C) in H-2 ambient. The Inductively Coupled Plasma (ICP) treatment was effected before and after the Schottky contact metallization, and two integrated hydrogen doses were imposed for the same low energy (500 eV/atom). Two deep levels were detected in the gap of the sample hydrogenated at the highest dose before contact deposition, similar to the double defect RD1/2 associated to the vacancy pair V-Si-V-C. No deep level was found on other plasma-hydrogenated samples, which electrical characteristics are the same than for virgin SiC. A slight improvement of electrical parameters (lowering of ideality factor, increasing of minority carrier diffusion length, better switching behaviour) was only measured on the sample annealed at 400 degrees C