Nanoscale SiGe-on-insulator (SGOI) MOSFET with graded doping channel for improving leakage current and hot-carrier degradation

A novel graded doping profile, for the first time is introduced for reliability improvement and leakage current reduction. The proposed structure is called graded doping channel SiGe-on-insulator (GDC-SGOI). The key idea in this work is to modify the electric field and band energy with novel doping distribution in the channel for improving leakage current and hot electron. Using two-dimensional two-carrier simulation we demonstrate that the GDC-SGOI shows lower electron temperature near the drain region in the channel in comparison with the conventional SGOI (C-SGOI) with uniform doping. On the other hand, short channel effects (SCEs) such as drain induced barrier lowering (DIBL) and threshold voltage roll-off improvement leads to leakage current reduction. DIBL decrement and less dependence of the threshold voltage and DIBL on channel length variation in the GDC-SGOI structure show SCEs suppression. Furthermore the on-off current ratio (I_on/I_off) in the GDC-SGOI is higher than that achieved from the C-SGOI. Therefore, the results show that the GDC-SGOI structure especially in low power and device reliability has excellent performance in comparison with the C-SGOI.