Aluminum doped silicon carbide thin films prepared by hot-wire CVD: Investigation of defects with electron spin resonance

作者：Xiao Lihong^*; Astakhov Oleksandr; Chen Tao; Stutzmann Martin; Finger Friedhelm

来源：Thin Solid Films, 2011, 519(14): 4519-4522.

DOI：10.1016/j.tsf.2011.01.320

• Hot-Wire chemical vapor deposition
• Microaystalline silicon carbide
• Al-doping
• Window layer
• Thin film solar cells

Al-doped p-type mu c-SiC:H is prepared in a wide range of HWCVD preparation parameters like Al-doping ratio, deposition pressure, substrate and filament temperatures. We investigate the structural and electrical properties, and focus on identification of paramagnetic defect states by electron spin resonance (ESR). Nominally undoped mu c-SiC:H is of a high n-type conductivity (sigma(D) = 10(-6)-10(-1)S/cm) and shows a narrow central ESR line (g approximate to 2.003, peak-to-peak linewidth Delta H(pp) approximate to 4 G) with two pairs of satellites and a spin density N(s) = 10(19) cm(-3). Al-doping results in the compensation of dark conductivity to as low as sigma(D) = 10(-11) S/cm and at higher doping concentrations to effective p-type material. Increase of Al-doping results in reduction of crystallinity (I(C)(IR)). ESR line shifts to g approximate to 2.01 and becomes as broad as Delta H(pp) approximate to 30 G, not unlike to the resonance of singly occupied paramagnetic valence band tail states in a-Si:H. ESR spectrum of highly crystalline Al-doped mu c-SiC:H however has a g-value very close to undoped mu c-SiC:H. Electron spin density in compensated material decreases to 5 x 10(17) cm(-3) before it increases again for the highly doped material.

• 出版日期2011-5-2