Influence of Block Oxide Width on a Silicon-on-Partial-Insulator Field-Effect Transistor

In this paper, the influence of block oxide width (W_BO) variations on a newly designed 40-nm gate-length silicon-on-partial-insulator field-effect transistor with block oxide (bSPIFET) was demonstrated and characterized. By utilizing the block oxide (BO) enclosing the sidewall of the Si body, the charge sharing from the source/drain (S/D) regions for a bSPIFET can be significantly reduced. Essentially, because the BO is adopted for a bSPIFET, its ultrashort-channel characteristics are similar to an ultrathin-body silicon-on-insulator (UTBSOI), although it possesses a thicker S/D region than a UTBSOI. From the simulation tests, it was also found that although the wider BO can suppress the ultrashort-channel effects (USCEs), the drain ON-state current I_ON slightly decreases because certain areas of the S/D are occupied by BO. Despite this problem, the bSPIFET still exhibits a good USCE control and a high-drive current. In addition, the self-heating effects are also ameliorated as a result of the natural body-tied scheme.