Semiconductor technology computer aided design

Technology computer aided design (TCAD) plays a crucial role in developing new process technologies, reducing the time to market and improving device design. Commercially available TCAD tools can now be described as virtual wafer fabs, where all aspects of device processing, electrical simulation, device testing and reliability analysis are available in a seamless software environment. This paper focuses largely on TCAD for CMOS, which is the workhorse of the silicon chip industry. The technology makes use of MOSFETs and a schematic diagram of such a transistor is shown. The two methods of device simulation each offer their own advantages and short-comings. The Monte Carlo method in effect includes all possible moments in its carrier distribution function. It is based on the physics of electronic band structure and specific scattering events, and so is fundamentally the more accurate method. An ensemble Monte Carlo simulation is shown, where a buried channel MOSFET is simulated. The calculation of leakage currents is straight forward for the method of moments, once differential equations have been solved. The concern with this approach is the validity and accuracy of the equations used