Volume 27, Number 1, January - February - March 2017

Thermo-mechanical Stress in Through-Silicon-Vias

During the last several years, the enhancement of integrated circuits (ICs) performance and power consumption have contributed to the continual scaling down the size of transistors. However, scaling down semiconductor devices has brought serious challenges to the materials and processes of on-chip interconnects beyond the 32-nm technology node. Therefore, some researchers proposed another direction to increase the device density by making ICs into three-dimensional (3D) spaces and the 3D IC stacking has attracted tremendous attention for IC integration in order to reduce wire length and footprint.

Simulation of a Bipolar Junction Transistor Under High and Low Current Injection Conditions

Semiconductor devices such as bipolar power transistors and solar cells may operate over a range of optical or electrical injection levels. In some cases of high injection, this may result in the occurrence of an electron-hole plasma somewhere in the device. For reliable device simulations, TCAD models need to cover the range of oper ating conditions and have models which depend on carrier densities, electric field, dopant densities, trap densities, and temperature. For the carrier mobilities, a Silvaco Device Simulator has several models that work well for high doping levels and high free carrier densities. For Shockley-Read-Hall carrier recombination, a Silvaco De vice Simulator has a range of options for trying to include the dependence of the recombination lifetimes on dopant densities, and one model to include the dependence on carrier density [1]. At very high carrier concentrations, however, the dominant carrier recombination mechanism is Auger recombination. In this process an electron- hole pair recombine across the bandgap and give the energy released to either an electron (eeh-process) or a hole (ehh-process). It has long been known that the standard expression for Auger recombination rate neglects some important physics at high carrier concentrations. Therefore two new models for Auger recombination in sil icon have been recently been included in a Silvaco Device Simulator, and are one of the two subjects of this article.

Hints, Tips and Solutions

Q: How do I extract geometric information, such as material thickness or junction depth, from the current 3D process simulation using Victory Process?

If you execute Victory Process in process mode, use the EXTRACT3D statement of Victory Process to extract properties of the 3D structure along a 1D line segment, such as layer thickness and position of the junction. For example, the following