Title :
An analytical model for the above-threshold characteristics of polysilicon thin-film transistors
Author :
Horng Nan Chern ; Lee, Chung Len ; Lei, Tan Fu
Author_Institution :
Dept. of Electron. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
fDate :
7/1/1995 12:00:00 AM
Abstract :
An analytical model for the above-threshold characteristics of long-channel, small-grain and thin channel polysilicon thin film transistors (TFT´s) is presented. This model is constructed by considering the barrier potential and the carrier trapping effect at grain boundaries of the channel. A band tail state located at Ec -0.15 eV is taken into account to simulate the I-V characteristics. Based on the model, the theoretically simulated results show good agreement with experimental data of plasma-passivated and unpassivated TFT devices in a wide range of gate and drain biases and temperature. The correlation of transconductance to gate bias is also investigated. It is found that the decrease of grain-boundary barrier potential with gate voltage enhances the transconductance, while this enhancement effect becomes insignificant and causes a decrease of transconductance at high gate bias
Keywords :
carrier mobility; defect states; elemental semiconductors; grain boundaries; semiconductor device models; silicon; thin film transistors; I-V characteristics; above-threshold characteristics; analytical model; band tail state; barrier potential; gate bias; grain boundary carrier trapping; long-channel TFT; plasma-passivated TFT; polysilicon thin-film transistors; small-grain TFT; temperature dependence; thin channel TFT; transconductance; unpassivated TFT; Analytical models; Grain boundaries; Plasma devices; Plasma properties; Plasma simulation; Plasma temperature; Tail; Temperature distribution; Thin film transistors; Transconductance;
Journal_Title :
Electron Devices, IEEE Transactions on
