Doping Procedure for Polycide
Original Publication Date: 1981-Dec-01
Included in the Prior Art Database: 2005-Feb-08
In the future, very large scale integrated MOSFET (metal oxide semiconductor field effect transistor) devices will incorporate a low resistive composite conductor, called polycide. It will be used as a device gate or word line (and/or bit line) of a circuit, to achieve an RC delay improvement of more than an order of magnitude over that of conventional polysilicon gates, or word lines. A polycide conductor consists of an underlying Layer of polysilicon (called pad polysilicon), a middle layer of transition metal silicide (for example, WSi(2), MoSi(2) or TaSi(2)) and a top layer of polysilicon overlay (called cap polysilicon). Currently, the doping of the conductor composite is done at the pad polysilicon level by the open tube POCl(3) method.