Ultrathin compound semiconductor on insulator layers for high performance nanoscale transistors

TL;DR

This paper demonstrates a novel epitaxial transfer method to integrate ultrathin single-crystalline InAs layers on Si/SiO2 substrates, creating high-performance nanoscale transistors with enhanced electrical properties and quantum confinement effects.

Contribution

It introduces a new epitaxial transfer technique for ultrathin InAs layers on Si-based substrates, enabling high-quality interfaces and improved transistor performance.

Findings

High transconductance (~1.6 mS/μm) achieved in InAs XOI transistors

Excellent ON/OFF current ratio (>10,000) demonstrated

Subthreshold swing of 107-150 mV/decade observed

Abstract

Over the past several years, the inherent scaling limitations of electron devices have fueled the exploration of high carrier mobility semiconductors as a Si replacement to further enhance the device performance. In particular, compound semiconductors heterogeneously integrated on Si substrates have been actively studied, combining the high mobility of III-V semiconductors and the well-established, low cost processing of Si technology. This integration, however, presents significant challenges. Conventionally, heteroepitaxial growth of complex multilayers on Si has been explored. Besides complexity, high defect densities and junction leakage currents present limitations in the approach. Motivated by this challenge, here we utilize an epitaxial transfer method for the integration of ultrathin layers of single-crystalline InAs on Si/SiO2 substrates. As a parallel to silicon-on-insulator (SOI) technology14,we use the abbreviation "XOI" to represent our compound semiconductor-on-insulator platform. Through experiments and simulation, the electrical properties of InAs XOI transistors are explored, elucidating the critical role of quantum confinement in the transport properties of ultrathin XOI layers. Importantly, a high quality InAs/dielectric interface is obtained by the use of a novel thermally grown interfacial InAsOx layer (~1 nm thick). The fabricated FETs exhibit an impressive peak transconductance of ~1.6 mS/{\mu}m at VDS=0.5V with ON/OFF current ratio of greater than 10,000 and a subthreshold swing of 107-150 mV/decade for a channel length of ~0.5 {\mu}m.