Circuit simulator including user-defined devices

We developed a circuit simulator capable of simulating circuits including any user-defined devices. Among various methods of implementing a device model into a circuit simulator, modifying the source program is the most powerful one. We have developed an environment for users to implement their device model with modifying of the device subroutine. This device subroutine serves as a window to put into their model. After compiling the subroutine, we can simulate circuits including any user-defined devices. We introduce not only the methodology for users to implement their models, but also the detailed implementation of a circuit simulator. We also developed a simple device model for an amorphous silicon thin-film transistor. The developed analytical model is in good agreement with experimental data. An inverter simulation has been studied to show that our circuit simulator is capable of simulating circuits including a-Si TFTs. Therefore, the circuit simulator can provide an environment in which to simulate more complex integrated circuits including a-Si TFTs.