Process of making doped polysilicon layers and structures and process of patterning layers and layer structures which contain polysilicon

摘要

In the production of a doped polysilicon layer and of layer structures containing such a layer, in which a doping compound is added to the process gas during CVD, the doping compound addition is terminated after achieving the desired doping and the desired deposition duration so that a boundary layer of undoped silicon layer is deposited. Preferably, the doping compound is a gaseous or volatile compound of B, Ga, In, P, As or Sb, especially diborane, trimethylboron, phosphine or arsine. Also claimed is a method of structuring a layer structure having a metal or metal silicide layer on a polysilicon layer by a three stage etching process using a fluorine-containing gas (preferably NF3, SiF4, SF6 and/or fluorinated hydrocarbon) in the first stage, a chlorine-containing gas (preferably HCl, Cl2 and/or BCl3) in the second stage and a bromine-containing gas (preferably HBr) in the third stage. Further claimed is a wafer or semiconductor chip produced using one or both of the above processes.