Strain‐Induced Effects on Band‐to‐Band Tunneling and Trap‐Assisted Tunneling in Si Examined by Experiment and Theory

Strain is commonly used in metal–oxide–semiconductor technologies to boost on‐state performance. This booster has been in production for at least a decade. Despite this, a systematic study of the impact of strain on off‐state leakage current has been lacking. Herein, experimental data and ab initio calculations are used to refine existing models to account for the impact of strain on band‐to‐band tunneling and trap‐assisted tunneling in silicon. It is observed that the strain may dramatically increase the leakage current, depending on the type of tunneling involved. For band‐to‐band and trap‐assisted tunneling, low uniaxial strains of 0.1% (or 180 MPa) can increase the leakage current by 60% and 10% compared to the unstrained case, respectively. Using models, it is predicted that compressive strain on the order of 1% (or 2 GPa) can increase the leakage current by 150 times. Conversely, tensile strain may diminish or at most double the leakage current in all observed cases. Though detrimental in conventional inversion‐mode metal‐oxide‐semiconductor field‐effect‐transistor, these processes may be used to boost the performance of tunnel field‐effect transistors, where on‐state current is defined by band‐to‐band tunneling.