Zoran Krivokapic

Tunneling and Short Channel Effects in Ultrascaled InGaAs Double Gate MOSFETs

Full-band quantum transport simulations are performed to study the scaling of InGaAs MOSFETs. Short-channel effects evoke severe performance degradation in InGaAs MOSFETs and the tunneling leakage further deteriorates their performances. Reducing the body width is shown to suppress the short channel effects. Doping densities show big impacts on device performances. With inhomogeneous doping InGaAs could outperform Si at gate lengths below 15 nm with 5-nm body width. The density of state bottleneck does not affect InGaAs in simulated devices at 0.5 V supply voltage. At the ultrascaled dimensions the full band simulations are essential to capture strong nonparabolic dispersion. Comparison with a multivalley effective mass model shows that the population of higher conduction band valleys contributes to the total current at thin body widths.

A comprehensive model for crossbar memory arrays

A crossbar array model with complete solutions for arbitrary memory and selector device behaviors (e.g., nonlinear, rectifying, etc.) is presented in this paper to analyze various array designs and device options. Voltage/current decay due to line resistance limits practical size of linear crossbar arrays below 10kbit. Less than 2% current reaches the end of a line in a small 1kbit array. Nonlinearity in memory characteristics and select diodes improve sensing margin from below 5% to above 30% in a 1kbit array. The voltage window between selected and unselected devices is increased from <;5%Vdd to >;20%Vdd by nonlinearity and >;40%Vdd by select diodes. This model provides quantitative evaluation for crossbar array designs and enables statistical analysis of array characteristics.