Impact of Yttria Spacer on the Performance of MgZnO/CdZnO Heterostructure

In the current study, we show the effects of the Y2O3 spacer layer on the mobility $(\mu)$, sheet carrier density $(n_{\mathrm{s}})$, and conductance $(n_{\mathrm{s}}\times\mu)$ of a MgZnO/CdZnO (MCO) heterostructure made by dual ion beam sputtering (DIBS). When compared to MCO heterostructures without a spacer layer, Hall measurements reveal that the addition of a 100-nm Y2O3 spacer layer increases mobility by almost four times. The impact of Cd content on the functionality of heterostructure should also be empirically investigated. The outcomes have important implications for the design of a large-area, low-cost heterostructure field-effect transistor (HFET) for sensors, microwaves, and power devices.

I. Introduction

CdZnO is being explored as a viable option for heterostructure field-effect transistor (HFET) applications due to the strong polarization fields in the MgZnO/CdZnO heterostructure [1] [2]. Khan et al. [2] have reported that the MCO heterostructure grown by DIBS has shown high sheet-charge density (~ 10¹⁴ cm^-2) and higher conductance (~10¹⁵ V⁻¹S⁻¹) at room temperature with Mg composition (x) i.e. 0.3 in the barrier layer of the Mg_xZⁿ1-_xO.