Effect of Uniaxial Strain on the Drain Current of a Heterojunction Tunneling Field-Effect Transistor

The electrical characteristics of a heterojunction tunneling field-effect transistor (HETT), with a p-type Si(0.75)Ge(0.25) source, have been measured as a function of strain. HETTs with channel transport and applied strain both in the [110] direction show a smooth monotonic change in drain current over a range of 0.09% compressive to 0.13% tensile strain. A measure gamma = (d/d ln J(D))(d ln J(D)/ds) vertical bar(s=0) of the effect of strain s on tunneling current J(D) is proposed, which captures the dependence of the tunneling exponential argument on strain. An experimental value of gamma = -11.7 is extracted for the tensile case and compared to simulation results. We found theoretically that the value and sign of. depend sensitively on the built-in strain at the Si-SiGe interface.