Analysis Of Transient Electrothermal Characteristics Of Field Transistor By Spectral Element Method

Semiconductor devices and integrated circuits composed by semiconductor devices are the basic units of the electronic equipment. With the higher degree of integration, the semiconductor technology continues to promote the rapid development of the integrated circuits technology. It improves the performance of electronic devices to meet the people’s rapidly changing demands for the technology progressing. The development of integrated circuit technology, in turn, promotes the constant progress of the semiconductor technology research. In the study of the semiconductor technology, the computational simulation plays a crucial important role in engineering practice for that it provides a reliable reference and guidance. So, there is a very important practical significance to study the numerical simulation of semiconductor devices.This thesis details the simulation of the FET’s transient electro-thermal characteristics by spectral-element time-domain method (SETD). The main contribution is shown as follows:Firstly, the formula of the drift-diffusion equations with the expression of SETD is detailed for silicon MOSFET. By solving the model equations with coupling method, the electrical characteristics are obtained under transient impulse. The formula of the heat conduction equation with the expression of SETD is detailed. By solving the heat conduction equation, the transient thermal characteristics are obtained. Then, considering the effect of temperature on the items such as impact ionization, mobility and other parameters, a coupled modeling of transient electro-thermal characteristics is achieved.Secondly, the formula of the drift-diffusion equations with schottky contact boundary conditions is derived for analyzing the transient electro-thermal characteristics of GaAs MESFET. Then, the formula of the drift-diffusion equations with the thermionic emission boundary condition and the schottky contact boundary condition is solved for analyzing the transient electro-thermal characteristics of GaAs/Si MESFET.Finally, a coupled method which combines the FET and the circuit is described. A detailed introduction to the choice of the trial solutions is provided. The simulation of a common source amplifier’s basic characteristics is achieved. The transient electro-thermal characteristics of MOSFET, which is an important part in the circuit, are obtained.