Thin Pt and Pd silicide Schottky barriers for silicon solar cells

Abstract

Metal silicide Schottky barriers allow reliable and stable rectifying contacts and can be attractive for silicon solar cells from both an economical and a technological point of view. Electrical properties of Pd₂Si and PtSi grown on silicon have been investigated as a function of silicide thickness ranging from 20 to 2000 AA. Thick Pd₂Si and PtSi films show resistivity of 43 and 35 mu Omega cm respectively; for thicknesses lower than 100 AA the resistivities increase suggesting a discontinuous structure of the silicide layers. Electrical characteristics and barrier heights of silicide Schottky diodes made on 5 Omega cm n-type silicon are independent of silicide thickness for thicknesses greater than 100 AA, while below this value they are affected by the discontinuity of silicide layers. The photoelectrical response shows a maximum for 150 AA thick PtSi and Pd₂Si films.