Power-supply voltage impact on circuit performance for half and lower submicrometer CMOS LSI

Based on theoretical understanding, the concept that the lower power supply voltage limit can be simply expressed by 1.1E_cL_eff, where E_c is the critical electric field necessary to cause carrier velocity saturation and L_eff is the effective channel length, is introduced. Experimental results confirmed that 1.1E_cL_eff predicts a good guideline for power-supply voltage for CMOS devices over a wide range of gate oxide thickness (7-45 nm) and design rule (0.3-2.0 μm). On the basis of theoretical models and experimental results, trends for power-supply voltage with MOS device scaling are demonstrated. It is shown that 1.1E_cL_eff can be regarded as the lower power-supply voltage limit in order to maintain the improvement in delay time for below 0.6-μm channel length at reduced power supply. The transconductance behavior for a MOSFET under high electric fields was investigated in order to explain the physical meaning of 1.1E_cL_eff