Tunneling Field-Effect Transistor: Effect of Strain and Temperature on Tunneling Current

Abstract

We report the first study of the effect of strain on tunneling field-effect transistor (TFET) characteristics. Double-gate silicon TFETs were employed. It was found that tensile strain increases the drain current, whereas compressive strain reduces the drain current. This is attributed to strain-induced band splitting and carrier repopulation and provides guidelines on strain engineering of TFETs. An elaborate study of the dependence of the electrical characteristics of TFET on temperature is also reported. It was observed that on-state tunneling current exhibits a positive temperature dependence at low drain bias condition ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> = 1 V), whereas opposite behavior was observed when <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> = 1.5 V. When the device temperature is increased, enhancement of the drain current at <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> = 1 V results from band gap narrowing, whereas reduction in the drain current at <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> = 1.5 V is attributed to the decrease in the electric field at the tunneling junction.