A new analytic model for amorphous silicon thin‐film transistors

We present a new theory describing current‐voltage characteristics of amorphous silicon thin‐film transistors. We calculate the output conductance in saturation by considering channel shortening effects caused by the space‐charge‐limited current in the pinch‐off region. In this model the drain current is expressed through the free‐carrier concentration at the source side of the channel. This allows us to obtain an accurate description of the different operating regimes of a thin‐film transistor using one equation that accounts for the dependence of the free‐carrier concentration in the channel for different regimes. Our model is in good agreement both with experimental data and the results of our two‐dimensional computer simulation. This approach allows one to account for different distributions of localized states in the energy gap. The model has also been developed to be incorporated into a circuit simulator and used for computer‐aided design of amorphous silicon integrated circuits.

[1]  Y. Nara,et al.  A Proposed Novel Amorphous-Silicon Image Sensor , 1980 .

[2]  Michael Hack,et al.  An analytic model for calculating trapped charge in amorphous silicon , 1988 .

[3]  J. Shaw,et al.  Two-Dimensional Simulations of Current Flow in Amorphous Silicon Thin-Film Transistors , 1988 .

[4]  K. Asama,et al.  A self-alignment process for amorphous silicon thin film transistors , 1982, IEEE Electron Device Letters.

[5]  N. Lustig,et al.  Temperature Dependent Characteristics of Hydrogenated Amorphous Silicon thin film Transistors , 1988 .

[6]  G. Cody,et al.  Recombination centers in phosphorous doped hydrogenated amorphous silicon , 1982 .

[7]  M. Shur,et al.  New high field‐effect mobility regimes of amorphous silicon alloy thin‐film transistor operation , 1986 .

[8]  W. Spear,et al.  Amorphous silicon p‐n junction , 1976 .

[9]  M. Shur,et al.  Physics of Novel Amorphous Silicon High-Voltage Transistor , 1987 .

[10]  Michael S. Shur,et al.  A new analytical model for heterostructure field‐effect transistors , 1989 .

[11]  J. Shaw,et al.  Simulations of short‐channel and overlap effects in amorphous silicon thin‐film transistors , 1989 .

[12]  Michael S. Shur,et al.  Physics of amorphous silicon based alloy field‐effect transistors , 1984 .

[13]  R. Street,et al.  Effects of doping on transport and deep trapping in hydrogenated amorphous silicon , 1983 .

[14]  K. Hiranaka,et al.  Self-alignment processed amorphous silicon ring oscillators , 1984, IEEE Electron Device Letters.

[15]  M. Shur,et al.  Above threshold characteristics of amorphous silicon alloy thin‐film transistors , 1984 .