Experiments were carried out to investigate the feasibility of metalorganic surface chemical adsorption deposition (MOSCAD) for growing aluminum nitride (A1N). This technique tends to promote only surface reactions, confining the decomposition, interactions between intermediates and deposition processes necessary for crystal growth to the substrate surface. As a result, low-temperature deposition becomes possible. Epitaxial A1N growth was demonstrated at a temperature as low as 400~ The A1N film, grown at a rate of 1.5-2.0 ~m/h, was visually observed to be transparent with a specular surface. The examination of the film by scanning electron microscopy at a magnification of twenty thousand revealed the featureless surface. X-ray diffraction of the film exhibited a single peak associated with A1N. Quantitative analysis by Auger electron spectroscopy revealed that only A1 and N were present in a ratio close to unity. These results indicate that MOSCAD is a viable alternative to MOCVD for AIN growth at a low temperature under atmospheric pressure.

Wet oxidation and computer simulation of metal oxide semiconductor (MOS) structures were studied on n‐type (Si‐face and C‐face) and p‐type (Si‐face) 6H‐normalSiC . The effects of thermal oxidation conditions at temperatures between 1100 and 1250°C on the electrical properties of MOS capacitors were studied. Oxidation model parameters for SSUPREM3 are presented, and simulation results are compared to laboratory studies with good agreement. The C‐V characteristics of the MOS capacitors were measured at high frequency in the dark and under illumination at room temperature. Samples prepared by wet oxidation showed accumulation, depletion, and inversion regions, but they did not show inversion regions under dark conditions. The interface trap densities and emission time constants of fast states were determined by ac conductance measurements. The electrical properties of normaln‐normaland p‐normaltype 6H‐normalSiC were compared. It was found that oxidation rate of C‐face was five to seven times faster than that of Si‐face on normaln‐normaltype SiC . The electrical properties of Si‐face and C‐face of normaln‐normaltype 6H‐normalSiC showed that the quality of oxide on the Si‐face was superior to the oxide on the C‐face.

Articles you may be interested inElectronic properties of metal-semiconductor and metal-oxide-semiconductor structures composed of carbon nanotube film on silicon Appl. Phys. Lett. 97, 233105 (2010); 10.1063/1.3524194 Electrical, structural, and chemical analysis of silicon carbide-based metal-oxide-semiconductor fieldeffect-transistors J. Appl. Phys. 95, 8252 (2004); 10.1063/1.1737801 Comparison of thermally oxidized metal-oxide-semiconductor interfaces on 4H and 6H polytypes of silicon carbide Electrical characterization of instabilities in 6H silicon carbide metaloxidesemiconductor capacitors J. Appl. Phys. 76, 993 (1994); 10.1063/1.357784Effects of gammaray irradiation on cubic silicon carbide metaloxidesemiconductor structure Fabrication processes of metal-oxide-semiconductor (MOS) capacitors on n-type, Si-face 6H-Sic, and its electrical properties, have been reported in this article. The effects of thermal oxidation conditions at temperatures between 1150 and 1250 "C on the electrical properties of MOS capacitors were studied. After oxidation, the wafers were annealed under argon ambient to improve the capacitance-voltage (C-v) characteristics. The C-V characteristics of the Al-Si02-SiC metal-oxide-semiconductor capacitors were measured at high frequency in the dark and under illumination. Under dark conditions, inversion did not occur, probably owing to the absence of minority carriers due to the large band gap of 6H-Sic. The C-V measurements made under illumination for both wet and dry thermally grown oxides show accumulation, depletion, and inversion regions. The ac conductance method was used to determine the interface trap densities and emission time constants of fast states. From the analysis of the data a total of fixed charges and the slow interface traps, N,t+NitslOw of 1.5-3.3 X 1012 cmm2, fast interface trap densities, NitFast of 0.5-1.7 X 10" cmm2 eV-t, and an emission time constant of 0.3-1.4 ps were obtained for wet oxidation. For dry oxidation, Not+Nitsrow of 3.5-l 1.2X 10" cmm2, NitFast of 0.7-1.25 X 10" cmm2 eV-', and emission time constants of 0.6-2 ys were obtained.1279

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Aluminum nitride thin films on silicon were electrically evaluated as a possible electrical insulator. The films were prepared by atmospheric pressure metal-organic chemical vapor deposition (MOCVD) over the temperature range from 300 to 500~ The thickness and refractive index of the A1N films was determined by ellipsometry. The electrical and compositional properties of the films were examined by the capacitance-voltage (C-V), ac conductance, and Auger electron spectroscopy (AES). The results suggest that the index of refraction and the film compositions are strongly dependent on the deposition temperature. A1N films prepared at higher deposition temperatures by MOCVD have good quality as compared with bulk single crystal A1N. The electrical behavior of these films and their relationship to substrate temperature and composition is discussed.