Volume 26, Number 3, October - November - December 2016

Victory Process 2D – A Valuable Alternative To SUPREM-based Simulators

SUPREM-IV – Stanford University PRocEss Modeling Program was first released 30 years ago. Since then its descendants - Athena from Silvaco and TSUPREM-4TM from TMA/Avant/Synopsys - have been 2D process simulation “work-horses” in semiconductor industry world-wide. Despite the fact that tremendous progress in the industry indeed requires the transition to 3D TCAD there are still many technologies and applications where a 2D simulation is the most practical approach. At the same time, we have to recognize that the SUPREM-based simulators cannot keep up with the progress because they lack many fundamental capabilities required for simulation of modern processes.

Stress Induced by Intrinsically Strained Silicon Nitride Passivation Films of AlGaN/GaN HEMTs Using Victory Process 2D

In the AlGaN/GaN HEMT fabrication process, silicon nitride (Si3N4) passivation of the HEMT surface layer, which is typically AlGaN, is commonly used to mitigate defect-related charge traps at the AlGaN surface. However, sufficiently thick Si3N4 passivation films manifest built-in or intrinsic stress that induces mechanical stress in underlying AlGaN/GaN HEMTs. Depending on deposition conditions, intrinsic stress in Si3N4 passivation films can be either compressive or tensile. Using Victory Process 2D to simulate stress induced by intrinsically strained passivation films of Si3N4 allows assessment of the influence such intrinsic stresses exerts on the AlGaN/ GaN HEMT performance.

TCAD Simulation of Impact Ionization at Cryogenic Temperatures, down to 3 K

Some electronic devices operate at very low, cryogenic temperatures, sometimes as low as 4 K, which is the temperature of liquid helium. Such devices include infra-red (IR) photodetectors or single-photon Avalanche Photo-Diodes (APD) (also known as a Geiger-mode APD or GAPD), based on a reverse biased p-n junction in which a photo-generated carrier can trigger an avalanche current due to the impact ionization mechanism. This device is able to detect low-intensity optical signals, e.g. single photon [1], [2].