Spacer-type thin-film polysilicon transistor for low-power memory devices

摘要

The cross-sectional area of a thin-film transistor (TFT) is decreased in order to minimize bitline to supply leakage of the TFT. This is accomplished by utilizing a spacer etch process to manufacture a TFT having a very narrow and thin channel in a controllable manner. The spacer dimensions of the TFT may be adjusted by simply modifying the thicknesses of the poly gate and the channel poly. The channel thickness is limited by the thickness of the deposited channel polysilicon which may be as thin as approximately 300 ANGSTROM to 500 ANGSTROM , and the channel width of the TFT corresponds to the height of the spacer etched along the polysilicon gate of the device which may be as small as approximately 0.15 to 0.25 mu m.