We demonstrate the capabilities of SILVACO TCAD tools for the design and simulation of intersubband GaAs/AlGaAs multiple quantum well infrared photodetectors. We compute the photoconductive gain spectrum of the device self consistently with the charge flow, non-radiative capture-escape, and intersubband transitions in the active region. The solid state calculations provide input to a light propagation modeling tool that allows for multiple reflections in the layered geometry of the active region. From this full calculation, we extract light absorption and quantum efficiency as a function of the angle of incidence and the wavelength of a mono-spectral beam of light. This TCAD simulation can be used as a starting point by design engineers for obtaining guide lines to analyze and optimize quantum well infrared photodetectors.

Fabrication of various nano-structures often requires mask controlled or patterned etching of materials. The chemical or wet etch methods cannot be used for nanoscale geometries due to the substantial isotropic component of etch rate. Therefore, various plasma or reactive ion etching method are typically used. Unfortunately, some materials do not easily form volatile reaction products and all types of chemically assist etching becomes problematic. Among those materials are elements such as Co, Ni, Fe, Pt, and Cr which are usually used in magnetic nano-structure technologies. Therefore, ion beam etching or ion milling is the most suitable method to pattern these materials [1].

In this article we describe a technique to automatically calibrate parameters of an Ion Enhanced Chemical Etching model implemented in the 3D process simulator VICTORY Process to measurements published in [1]. We will briefly describe the model and show how an experiment applying this model can be set up in VWF to automate the calibration by carrying out several individual simulations without user interaction.

The three-dimensional process simulator VICTORY Process now includes a semi-empirical model for the simulation of ion milling. During ion milling, the mill (etch) rate depends in a complex way on the local beam’s incidence angle (angle between beam direction and the normal at a particular surface point). The function describing this relationship is called the angle dependent mill rate. A visual representation of such an angle dependent mill rate is shown in Figure 1.

Accurate stress simulation has become a necessary part of performance and reliability analysis of semiconductor devices. In our previous paper [1] we demonstrated that 3D stress simulation of the whole cell provides more accurate prediction of stress effects on device performance than simulation limited to individual devices.