Method for making polycrystalline silicon film resistors.

摘要

A method for making polycrystalline silicon film resistors is described which includes deposition of a polycrystalline silicon layer (14, 34) of very fine grain size upon an insulator surface (12, 28), followed by ion implantation of boron equal to or slightly in excess of the solubility limit of the polycrystalline silicon. This ion implantation is normally done using a screen silicon dioxide surface layer. The structure may be annealed at temperatures of between 800°C to 1100°C for 15 to 180 minutes to control the grain size of the polycrystalline silicon layer, homogenize the distribution of the boron ions throughout the entire film thickness and to raise the concentration of the boron in the silicon grains to the solid solubility limit. The suitable electrical contacts (52, 54) are now made to the polycrystalline silicon layer to form the resistor.