A novel simplified process for fabricating a very high density p-channel trench gate power MOSFET

A novel simplified fabrication method of a very high density p-channel trench gate power MOSFET using four mask layers and nitride/TEOS sidewall spacers is realized. The proposed process showed improved on-resistance characteristics of the device with increasing cell density and the cost-effective production capability due to the lesser number of processing steps. By using this process technique, a remarkably increased high density (100 Mcell/inch
²
) trench gate power MOSFET with a cell pitch of 2.5 μm could be effectively realized. The fabricated device had a low specific on-resistance of 1.1 m/spl Omega/-cm
²
with a breakdown voltage of -36 V.