Study On Threshold Voltage Models For Silicon-based Ge Channel MOSFET

Threshold voltage is one of the most important parameters of MOSFET. Thresholdvoltage will directly affect the channel trans and the working voltage of devices. Andfor the small size of device, if the channel doping is overweight, it will lead to anincrease of threshold voltage, increase the power consumption and greatly reduce devicereliability. And, as the decrease of the channel length and the gate oxide thickness, thegrid control charge will reduce, which will be significant short channel effect,whichcan seriously affect threshold voltage, thus establishing effective and reasonablethreshold voltage model to the design of the preparation and MOS device is verynecessary.At present, the research of silicon-based Ge channel MOS device major haveburied layer in gully channel and surface, the device is mostly SiGe buffer layer asvirtual substrate. There are the experiment research of Ge channel pMOSFET, but theresearch of the device model is very little, especially the threshold voltage modelresearch report has not been seen at home and abroad. An analytical model on thresholdvoltage of Ge channel pMOSFET is developed by solving Poisson’s equation first timein this paper. Short channel effect and drain induced barrier lower are taken into themodel. The results of the calculation model is coincides with the experimental data.And then using the established model to analyze the various parameters of the devicesuch as the channel length, the gate oxide layer thickness, substrate dopingconcentration on the threshold voltage effects.