Development of Schottky barrier field-effect transistors (SB-MOSFET) with ultra-low thermal budget

Abstract

This work presents the development of SB-MOSFET transistors incorporating thin HfO2 as a thin gate dielectric deposited by thermal atomic layer deposition (ALD) at low temperature. Aluminum thin films were used as the source/drain (S/D) and gate (G) electrodes, using e-beam evaporation at high-vacuum conditions. Even though low subthreshold slope (SS) values of 111 mV/dec and threshold voltage (Vth) of 0.58 V were obtained using a low thermal budget of 150 °C for transistor fabrication, scanning electron microscopy (SEM) analysis highlights the importance of proper mask alignment in order to enhance electrical performance and thus, reproducibility of the electrical characteristics of this device. This device can be fully integrated into silicon after standard Complementary Metal-Oxide-Semiconductor (CMOS)-compatible processing, so that it could be easily adopted into Front-End-Of-Line or even in Back-End-Of-Line stages of an integrated circuit, where low thermal budget is required and where its functionality could be increased by developing additional and fast logic.