BARRIER HEIGHT IN N-SIC-6H BASED SCHOTTKY DIODES

Metal-n-SiC-6H (metal=Au, Mo, Cr, or Al) surface-barrier structures wi th uncompensated donor impurity concentrations N-d-N-a = 4.10(16)-3.10 (18) cm(-3) were investigated. For N-d-N-a = 1.10(17) cm(-3) the exper imentally determined average barrier height was similar to 1.40, 1.30, 1.22, and 1.26 eV in gold, molybdenum, chromium, and aluminum based S chottky diodes, respectively. It was observed that as N-d-N-a increase s, a lower barrier tends to form in these structures. The method emplo yed for producing Schottky barriers which includes short-time treatmen t in KOH of the surface obtained after the growth of epitaxial layers or after preliminary sublimation etching of the substrates leads to a high surface state density, as a result of which the barrier height is virtually independent of the work function. A comparative analysis wa s performed of the obtained results and the experimental data of diffe rent authors on the barrier height. The barrier height in metal-n-SiC- 6H structures was calculated on the basis of the classical model. (C) 1995 American Institute of Physics.