AVS 62nd International Symposium & Exhibition
    Electronic Materials and Processing Thursday Sessions
       Session EM+MS-ThA

Paper EM+MS-ThA10
Plasma Enhanced Atomic Layer Deposition of Al2O3 on AlGaN/GaN High Electron Mobility Transistors

Thursday, October 22, 2015, 5:20 pm, Room 210E

Session: III-N Nitrides II
Presenter: Xiaoye Qin, University of Texas at Dallas
Authors: X. Qin, University of Texas at Dallas
R.M. Wallace, University of Texas at Dallas
Correspondent: Click to Email

Metal insulator semiconductor AlGaN/GaN high electron mobility transistors (MISHEMTs) are promising for power device applications due to a lower leakage current than the conventional Schottky AlGaN/GaN HEMTs. Among a large number of insulator materials, Al2O3 dielectric layer, deposited by atomic layer deposition (ALD), is often employed as the gate insulator because of a large band gap (and the resultant high conduction band offset on AlGaN)1, high breakdown field, conformal growth, and a relatively high dielectric constant. However, the thermal ALD Al2O3 does not passivate the surface effectively according to our previous work.1–4 In this work, the half cycle study of plasma enhanced atomic layer deposited (PEALD) Al2O3 on AlGaN is investigated using in situ X-ray photoelectron spectroscopy (XPS), low energy ion scattering (LEIS) and ex situ electrical characterizations. A faster nucleation or growth is detected in PEALD than thermal ALD using an H2O precursor. The PEALD Al2O3 layer decreases the gate leakage current as the ALD Al2O3. Importantly, the remote O2 plasma oxidizes the AlGaN surface slightly at the initial stage, which passivates the surface and reduces the OFF-state leakage. This work demonstrates that PEALD is a useful strategy for Al2O3 growth on AlGaN/GaN devices.

This work was supported by the Asian Office of Aerospace Research and Development (AOARD) through the Air Force Office of Scientific Research (AFOSR) under Grant No. FA2386-14-1-4069.

Reference

1 X. Qin, L. Cheng, S. McDonnell, A. Azcatl, H. Zhu, J. Kim, and R.M. Wallace, J. Mater. Sci. Mater. Electron. In press (2015).

2 X. Qin, B. Brennan, H. Dong, J. Kim, C.L. Hinkle, and R.M. Wallace, J. Appl. Phys. 113, 244102 (2013).

3 X. Qin, A. Lucero, A. Azcatl, J. Kim, and R.M. Wallace, Appl. Phys. Lett. 105, 011602 (2014).

4 X. Qin, H. Dong, J. Kim, and R.M. Wallace, Appl. Phys. Lett. 105, 141604 (2014).