Formation of polysilicon resistors in the tungsten strapped source/drain/gate process

摘要

A semiconductor device having tungsten strapped gate electrodes and source/drain regions and a polysilicon resistor. The gate electrodes and the polysilicon resistors are all formed from the same layer of polysilicon by initially coating the deposited polysilicon layer with an insulating layer and subsequently a layer of phosphorus doped silicon glass. The electrodes and resistor areas are formed by selectively etching the silicon glass and the polysilicon. This leaves the electrode polysilicon and the resistor polysilicon coated with the phosphorous doped glass. Spacers are then provided along the electrode and the glass removed only from above the gate electrode polysilicon leaving the resistor coated with the phosphorus doped silicon glass and silicon nitride. Tungsten then can be selectively deposited upon the gate electrode and along adjacent source and drain regions. This takes advantage of the use of selectively deposited tungsten over gate electrodes and at the same time eliminates the need to deposit separate polysilicon layers for the resistors.