Effect of band-to-band tunnelling leakage on 28 nm MOSFET design

The effect of band-to-band tunnelling leakage on 28 nm MOSFETs is studied using TCAD simulation. For low-standby power applications, the leakage current of the MOSFET is increasingly dominated by GIDL instead of a subthreshold leakage as the S/D extension doping increases. The GIDL current can be reduced by relaxing the lateral abruptness of the drain at the expense of a higher S/D series resistance. Based on the simulated results, we have found that a very limited margin in S/D design is allowed to meet both leakage current and performance requirement for 28 nm MOSFETs.