Reliable determination of the Cu/n-Si Schottky barrier height by using in-device hot-electron spectroscopy

TL;DR

This paper demonstrates a hot-electron transistor method for accurately measuring the Cu/n-Si Schottky barrier height at low temperatures, providing a reliable alternative to traditional complex fitting techniques.

Contribution

It introduces a hot-electron spectroscopy approach using a Cu/Al2O3/Cu/n-Si transistor for direct barrier height measurement at low temperatures, showing consistent results with established methods.

Findings

Barrier height of 0.66 eV at temperatures below 180 K

High ON/OFF ratio of 10^5 and low OFF current (~2×10^-13 A)

Subthreshold swing of ~96 mV/dec suitable for high-frequency applications

Abstract

We show the operation of a Cu/Al_2O_3/Cu/n-Si hot-electron transistor for the straightforward determination of a metal/semiconductor energy barrier height even at temperatures below carrier-freeze out in the semiconductor. The hot-electron spectroscopy measurements return a fairly temperature independent value for the Cu/n-Si barrier of 0.66 $\pm$ 0.04 eV at temperatures below 180 K, in substantial accordance with mainstream methods based on complex fittings of either current-voltage (I-V) and capacitance-voltage (C-V) measurements. The Cu/n-Si hot-electron transistors exhibit an OFF current of ~2 * 10^-13 A, an ON/OFF ratio of ~10^5 and an equivalent subtreshold swing of ~96 mV/dec at low temperatures, which are suitable values for potential high frequency devices.