GaN基HEMT器件的缺陷研究综述

GaN基高电子迁移率晶体管(HEMT)因具有高输出功率密度、高工作频率、高工作温度等优良特性,在高频大功率等领域具有广泛应用前景。目前,HEMT器件在材料生长和工艺制备方面都取得了巨大的进步。但是,由缺陷产生的陷阱效应一直是限制其发展的重要原因。本文首先论述了HEMT器件中的表面态、界面缺陷和体缺陷所在位置及其产生的原因。然后,阐述了由陷阱效应引起的器件电流崩塌、栅延迟、漏延迟、Kink效应等现象,从器件结构设计和工艺设计角度,总结提出了改善缺陷相关问题的主要措施,其中着重总结了器件盖帽层、表面处理、钝化层和场板结构4个方面的最新研究进展。最后,探索了GaN基HEMT器件在缺陷相关问题上的未来优化方向。

Reviews on Trapping Effects of GaN-based HEMTs

High electron mobility transistors (HEMTs) based on GaN have a promising prospect in the fields of high frequency and high power due to their advantages of high output power density, high operating frequency and high operating temperature.At present, great progress has been made in material growth and fabrication processes of HEMTs.However, the trapping effect produced by the defect limits the development of HEMTs.In this paper, the surface states, interface defects and bulk defects of HEMT devices and the causes of these defects were discussed.The phenomenon caused by trap effect such as the current collapse, gate lag, drain lag and kink effect were also described in detail.The main approaches to improve the defects were summarized from structure design and process design.And the latest progresses focusing on the four aspects of the capping layer, surface treatment, passivation layer and field plate structure were reviewed.Further optimization in the defect of the GaN based HEMT devices was explored at the end.