Experimental study of nonlinear current-voltage behavior in undoped polycrystalline silicon

Abstract

Electrical conduction data from undoped low-pressure chemically vapor deposited polycrystalline silicon thin films at room temperature and above are presented. The physical mechanisms pertinent to general current-voltage characteristics are experimentally interrogated from three different viewpoints. In the nonlinear current-voltage region, the sheet resistance Rs is shown to vary drastically depending on the device aspect ratio for given applied electrical field Ē. The nonscalability of Rs with respect to Ē, the temperature behavior of Rs, and the photoconductivity data indicate that the nonlinear current-voltage behavior cannot be attributed to field-enhanced conductivity. Other possible mechanisms responsible for observed nonlinearity are discussed.