A new self-aligned contact technology

A new self-aligned contact technology suitable for high density MOS VLSI is proposed. This technology includes phosphorus doped polysilicon oxidation under high pressure and low temperature, and the formation of polysilicon cover or interconnection on self-aligned contact region. Large differential oxidation ratio (5:1) of doped polysilicon to lightly doped silicon substrate can be easily obtained. The SiO2film on the polysilicon gate acts as an excellent interlevel insulator. It is verified that this technology is readily applicable to conventional Si-gate MOS processes. Further, packing density increase of MOS VLSI due to this technology is estimated.