Method of fabricating a semiconductor device with a polycrystalline silicon resistive layer

摘要

Provided is a novel method of fabricating a polycrystalline silicon layer serving as a resistive element involved in a high frequency semiconductor integrated circuit device. The novel method essentially comprises following steps. A polycrystalline silicon layer is deposited on an insulation layer covering a semiconductor substrate, followed by a selective photo etching by using a photo resist as a mask, and further followed by a selective doping by using ion-implantation with employing a photo resist pattern so as to introduce dopant into the remaining polycrystalline silicon layer except for a peripheral area having a predetermined width thereby resulting in a resistive layer which comprises not only a doped area but an undped area fencing the doped area.