Polycide process

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As a polycide process (Engl.) Is known in the semiconductor technology , a method in which a silicide of a (closed) polysilicon layer is formed. The process is widely used in DRAM production for the production of word-line conductor tracks and MOSFETs.

The process, which was introduced in the 1970s, represents an improvement on the polysilicon gate technology used at that time for the production of integrated circuits . As with all silicide processes, a metal layer is first applied, (in the initial phase) mainly tungsten , deposited on the closed, possibly highly doped polysilicon layer. This is followed by a high-temperature step to diffuse the metal into the polysilicon and form a low-resistance phase. The exact process conditions depend on which metal is used or which silicide is to be formed. The specialty of the Polycide process is that the silicide is only formed in the upper area of ​​a polysilicon layer before it is structured. It is in contrast to other silicidation processes in which the silicide is formed after polysilicon etching, for example the salicide process , in which silicide is formed in a self-aligning manner both over the polysilicon gate and over the exposed monocrystalline areas.

literature

  • MY Tsai et al. a .: One ‐ Micron Polycide (WSi2 on Poly ‐ Si) MOSFET Technology . In: Journal of The Electrochemical Society . tape 128 , no. 10 , October 1, 1981, p. 2207–2214 , doi : 10.1149 / 1.2127219 ( limited preview in Google Book search).