Atomic layer deposition of Y2O3 on h-BN for a gate stack in graphene FETs

TL;DR

This study explores atomic layer deposition of Y2O3 on h-BN for use as a gate insulator in graphene FETs, highlighting the effects of temperature and seeding layers on coverage quality.

Contribution

It demonstrates successful Y2O3 deposition on h-BN without buffer layers and introduces a seeding layer technique to improve surface coverage.

Findings

Full coverage achieved with oxidized metal seeding layer

Higher deposition temperatures reduce surface coverage

Deposition mechanism involves competition between desorption and adsorption

Abstract

The combination of h-BN and high-k dielectrics is required for a top gate insulator in miniaturized graphene field-effect transistors because of the low dielectric constant of h-BN. We investigated the deposition of Y2O3 on h-BN using atomic layer deposition. The deposition of Y2O3 on h-BN was confirmed without any buffer layer. An increase in the deposition temperature reduced the surface coverage. The deposition mechanism could be explained by the competition between the desorption and adsorption of the Y precursor on h-BN due to the polarization. Although a full surface coverage was difficult to achieve, the use of an oxidized metal seeding layer on h-BN resulted in a full surface coverage.