Behavior of polysilicon thin-film transistors at different temperatures

A correlation between the material quality of the undoped polysilicon active layer of Thin Film Transistors and the behavior of the transistor parameters at different temperature is highlighted in this study. With low quality material, the transconductance g(m) decreases monotonically with decreasing temperatures. Such behavior originates from the scattering at the grain boundaries, which is predominant even at high temperature. With high quality material, g(m) increases with decreasing temperatures in the high temperature range and then becomes constant, independent of the temperature, in the low temperature range. At high temperature, the thermal scattering is predominant as in single crystalline MOSFET.