Growth on GaN and GaAs on fianite by MOCVD capillary epitaxy technique
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Internet Journal Nitride Semiconductor Research
Growth on GaN and GaAs on fianite by MOCVD capillary epitaxy technique A. N. Buzynin1, V. V. Osiko1, Yu. N. Buzynin2 and B. Pushnyi3 1General
Physics Institute of RAS, for Physics of Microstructure of RAS, 3Ioffe Physical-Technical Institute, 2Institute
(Received Monday, June 22, 1998; accepted Wednesday, November 4, 1998)
Heteroepitaxial GaN and GaAs films were grown by both conventional two-step MOCVD and the new “capillary epitaxy” technique on (001) and (111) fianite (YSZ) substrates. The capillary epitaxy technique was investigated for the example of GaAs films growth on a YSZ substrate. This technique allows both the reduction of the minimum thickness and the improvement of the quality of III-V films. PL spectra of undoped GaN films on YSZ were studied.
1
Introduction
Fianite (or yttria stabilized zirconia - YSZ) has a number of significant advantages in comparison with other insulating substrate materials, as follows: good insulating properties (1012Om.cm at 300K); and high optical transmission in a wide wavelength range including the visible. Fianite is a good epitaxial partner for AIIIBV compounds because of their crystallochemical and physical characteristics (table 1). Epitaxial Si films on YSZ prepared by the pyrolysis of silane in a hydrogen atmosphere [1] and by the chloride vapor phase technique [2] at a temperature of more than 1000°C have been reported. To diminish the negative role of the difference in thermal expansion coefficients between epitaxial pairs it is necessary to lower the epitaxial temperature to about 650°C. We have reported about thin GaAs films on YSZ prepared by the metallorganic chemical vapor deposition (MOCVD) [3]. GaAs films on YSZ substrates have better properties than those on either sapphire or SI-GaAs due to better structural and electrical characteristics, and better thermal and radiation stability. In this paper we report new results about GaN and GaAs films grown on YSZ substrates by the MOVPE and “capillary epitaxy” [4] technique. The source materials were TMG and AsH3 for GaAs or NH3 for GaN3 films. The films have been characterized by electron microscopy (TEM and SEM), X-ray diffraction (XRD), reflection high-energy electron diffraction (RHEED),
luminescence, secondary - ion mass spectroscopy (SIMS) and Van der Pauw measurements. 2 2.1
Experiment Preparation of the YSZ Substrates
The single YSZ crystals, consisting of ZrO2 stabilized with 10, 15 and 21 mole per cent of Y2O3, were grown by the skull melting technique [5] at 3000°C in air (RF power – 160 kW, frequency – 1.67 MHz). The YSZ crystal block dimensions were large (40-80 mm in cross section and 80-100 mm in length). As-grown YSZ crystals can have both block crystalline and single crystalline structure. We used only single crystalline YSZ with the best structural perfection for wafer preparation. YSZ (100) and (111) oriented wafers were prepared by a multistage technique [6] using ultra dispersed diamond at the mechanical treatment stage. The chemical c
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