Design Of SiCGe/SiC Light-Activated Darlington Transistors And Growth Of SiCGe/SiC Heterojunction

With the development of the sic device intensive research, there has been a growing interest in SiC light-actived devices. However, due to the SiC materials has wide bandgap sic light-actived switchs only work in UV wavelength range no in the either near-infrared or visible wavelangth range. On taking into account practice applications, in order to make the device realized in practice, By using a ternary alloy SiCGe with a narrower energy gap than SiC material, we have proposed a monolithically integrated SiCGe/SiC light-activated Darlington tansistor, in which SiCGe/SiC Heterojunction pn diode was employed to drive SiC darlington transistor. This dissertation aims at the developing of SiCGe/SiC light-activated Darlington tansistor. in which the researth work included design of device struction, the fabrication of SiCGe/SiC Heterojunction and characteristics of SiCGe/SiC Heterojunction. The main researth work and conclustion are as following.1. After feasibity of the new design was successfully tested by means of the two-dimensional device simulator MEDICI, on taking into account practice technics, we present many of improved design of the siC light-activated darlington transistors, in which only one hetero-epitaxy is required to make a monolithically integrated SiCGe/SiC heterojunction photodiode that provides a primary base current to drive the SiC Darlington transistor. This simplifies processing of device fabrication.2. Optimum design of struction and characteristics of the improved devices have been finished, the simulation resisults indicate that by means of a ternary alloy SiCGe with appropriate compositon, the novel light-activated device has very good optical switching characteristics for a commonly used visible or near-infrared triggering light.3. The two set of horizontal hot-wall CVD for hetero-epitaxial growth of SiCGe and p-type SiCGe on the SiC substrate have been made, respectively. For the sake of obtaining uniformity epitaxial film, In development of the equipment, first, by means of the finite element method, simulations involving electromagnetic, heat and mass transfer were performed on this hot-wall CVD reactor to quantify the complex both temperature and flow distribution, then the design parameters of heating module have been optimized with innovation.