Kaiser, S. and Jakob, M. and Zweck, Josef and Gebhardt, W. and Ambacher, O. and Dimitrov, R. and Schremer, A. T. and Smart, J. A. and Shealy, J. R. (2000) Structural properties of AlGaN/GaN heterostructures on Si(111) substrates suitable for high-electron mobility transistors. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 18 (2). pp. 733-740. ISSN 1071-1023
Full text not available from this repository.Abstract
Transmission electron microscopy (TEM) investigations of metal organic vapor phase deposition grown AlxGa1 - xN/GaN heterostructures on Si(111) containing an AIN high-temperature buffer layer have been carried out. The structural properties at the interface and in the epilayer as well as the electronic properties suitable for a high electron mobility transistor (HEMT) were analyzed and compared with systems grown on Al2O3(0001). High resolution TEM (HRTEM) at the AlN/Si(111) interface reveals a 1.5-2.7 nm thick amorphous SiNx layer due to the high growth temperature of T-AIN = 1040 degrees C. Therefore, a grain-like GaN/AlN region extending 40-60 nm appears and it is subsequently overgrown with (0001) orientated GaN material because of geometrical selection. The residual strain at the AlN/Si(111) interface is estimated to be epsilon(r) = 0.3+/-0.6% by Fourier filtering of HRTEM images and a moire fringe analysis. This indicates almost complete relaxation of the large mismatch f(AlN/Si)= +23.4% which seems to be supported by the SiNx layer. Weak beam imaging and plan view TEM show typical threading dislocations in the epilayer with a density of 3x10(9) cm(-2) extending along < 0001 > which sometimes form grain boundaries. An AlxGa1 - xN/GaN interface roughness of 3 monolayers is estimated and a small AlxGa1 - xN surface roughness of 1.5 nm is obtained by HRTEM and atomic force microscopy investigations which correspond to two-dimensional growth. C-V and Hall measurements reveal two-dimensional electron gas at the Al32Ga68N/GaN interface that has a sheet carrier concentration of 4x10(12) cm(-2). The electron mobility of 820 cm(2)/Vs measured at room temperature is applicable for a HEMT grown on Si(111). (C) 2000 American Vacuum Society. [S0734-211X(00)06002-9].
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | MOLECULAR-BEAM EPITAXY; LIGHT-EMITTING-DIODES; GAN; NITRIDE; SILICON; GROWTH |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Back > Group Josef Zweck |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 31 May 2022 08:39 |
| Last Modified: | 31 May 2022 08:39 |
| URI: | https://pred.uni-regensburg.de/id/eprint/42797 |
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