Analysis of Drain Current in Polycrystalline MgZnO/ZnO and MgZnO/CdZnO HFET

Abstract

In this article, we report on estimating the drain current (Id) characteristics of polycrystalline MgZnO/ZnO (MZO) and MgZnO/CdZnO (MCO) heterojunctions-based heterostructure FET (HFET). The developed model utilizes ionized interface state density (Qi) and its interrelationship with the barrier layer thickness (d), Mg content (x), and electron mobility (μ) to account for the interface defects and their variations with electrical and physical parameters of polycrystalline heterointerface-based ZnO HFETs. The results suggest that the saturation drain current (Idsat) in MCO HFET can be comparable to that in MZO HFET when Qi enhancement is considered along with the reduction in μ. This article has extensively explored major relationships of Qi, which governs Id in HFETs, with d and x to convincingly postulate that the experimental Id in polycrystalline MZO-and MCO-based HFETs could be a combination of the two extreme cases of Qi dependent and independent on d and x. This article is significant to enhance the understanding and therefore optimizing the direct current (dc) performance of polycrystalline ZnO HFETs. © 1963-2012 IEEE.