Study On Spice Modeling For Strained Si/SiGe MOSFET

At present Spice can simulate Si device and circuit, but existing version Spice has no Strained Si/SiGe models, simulation of Strained Si/SiGe circuit could not be accomplished. So it is urgent to establish the Strained Si/SiGe model based on Spice for circuit simulation.The following is the major element in this paper.(1)Based on the MOS1 model of Si MOSFET equivalent circuit in Spice,equivalent circuit models of both the surface channel strained silicon N/P MOSFET and the strained SiGe quantum well channel PMOSFET are established.(2)Considered the physics mechanism and suppose the potential along channel changes with the square of the distance, two dimension possion equation can be simplified into one dimension. By this means, the threshold voltage model for the surface channel strained silicon N/P MOSFETs and strained SiGe quantum well channel PMOSFET are established.(3) Polynomial Parameter fitting theory is applied for calculating the mobility enhance factor model of the surface channel strained silicon N/P MOSFET and the strained SiGe quantum well channel PMOSFET , which makes mobility possible to directly use the model in Spice.(4)After received the model of threshold voltage and mobility,it is convenient to account the I-V model.According to structure of the strained SiGe quantum well channel PMOSFET,consider the influence made by the cap current,the perfect model of I-V for the strained SiGe quantum well channel PMOSFET is established.(5)Based on the I-V model ,the transconductance and drainconductance of the surface channel strained silicon N/P MOSFET and the strained SiGe quantum well channel PMOSFET are builded.