TEMPERATURE EFFECTS ON HEAVILY-DOPED POLYCRYSTALLINE SILICON

The effects of operating temperature and current density on the resistivity of low-pressure chemical-vapor-deposition polycrystalline silicon heavily doped with different impurities, phosphorous (3.1x10(20) cm(-3)), arsenic (4.6X10(20) cm(-3)), or boron (3.1x10(20) cm(-3)), were studied. The resistivity of the films was measured over a wide range of temperatures (15-195 degrees C) and current levels (1-20 mA). The arsenic-doped polycrystalline silicon results agree with the widely used thermionic emission model; however, unexpected results were obtained for the phosphorous- and boron-doped samples where the resistivity increases with temperature and current density. For the phosphorous and boron-doped materials, an empirical model based on carrier mobility that can predict the resistivity of the polycrystalline silicon over a wide range of operating temperatures and current densities has been developed; the agreement between the model predictions and the experimental data is good.