| AVS 60th International Symposium and Exhibition | |
| Electronic Materials and Processing | Monday Sessions |
| Session EM+TF-MoM |
| Session: | High-k Gate Oxides for High Mobility Semiconductors I |
| Presenter: | X. Qin, University of Texas at Dallas |
| Authors: | X. Qin, University of Texas at Dallas B. Brennan, University of Texas at Dallas H. Dong, University of Texas at Dallas A. Azcatl, University of Texas at Dallas R.M. Wallace, University of Texas at Dallas |
| Correspondent: | Click to Email |
AlGaN/GaN high electron mobility transistors (HEMTs) are of significant interest for high power, high frequency and high temperature devices due to their large band gaps, high mobility and chemical stability compared to Si and other high mobility III-V materials. However, a large leakage current and frequency dependent current collapse degrades the performance of AlGaN/GaN HEMTs. The surface passivation process consisting of a suitable surface treatment and growth of a high-k oxide layer between the semiconductor and the gate metal is one of the proposed methods to address these issues.
In this study, we investigate atomic layer deposition (ALD) of Al2O3 on the native oxide, N2 plasma and forming gas plasma exposed AlGaN surface, respectively. X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) is used to determine the interface after N2 or forming gas plasma exposure. Initial results indicate that N2 or forming gas plasma is able to remove carbon and decrease the concentration of oxygen. And the contamination level is lower than various alternative wet chemical treatments. The interaction between the Al2O3 and the AlGaN surfaces during deposition is also studied by XPS. The XPS and LEED are carried out in-situ by transferring the samples between the plasma chamber, the ALD reactor and the analysis chamber under UHV conditions (< 2 x 10-10 mbar) to prevent contamination due to atmospheric exposure.
The work is supported by the AOARD under AFOSR Grant No. FA2386-11-14077