硅基锗薄膜的红外吸收谱和电学特性

为了解退火对硅基锗薄膜的质量、红外吸收、透射率和电学性质的影响,采用分子束外延方法用两步法在硅基上生长锗薄膜。将生长后的样品分成两部分,其中一部分进行了退火处理。对退火前后的样品用高分辨X射线双晶衍射仪测量了(400)晶面的X射线双晶衍射摇摆曲线,用傅里叶红外光谱仪测量了红外透射率和吸收谱,并用霍尔效应仪测量了退火前后样品的载流子浓度、迁移率、电阻率、电导率和霍尔系数。结果表明,退火后的薄膜质量明显提高。退火后大部分区域吸收增大,透射率明显减小,615~3 730 cm-1区间的透射率均比退火前降低了20%以上。退火后的体载流子浓度增大到退火前的23.26倍,迁移率增大到退火前的27.82倍。

Infrared Absorption Spectra and Electrical Properties of Si Substrate Ge Thin Films

In order to understand the influence of annealing on the epitaxial film quality and optoelectronic properties, an epitaxial Ge film was grown on a Si(001) substrate via the two-step process using molecular beam epitaxy technique. The sample was divided into two pieces, and one piece of the sample was annealed. X ray double crystal diffraction rocking curves of (400) crystal plane for non-annealed and annealed epitaxial Ge films were measured by the high resolution double-crystal X-ray diffractometer. Fourier transform infrared transmittance and absorption spectra for non-annealed and annealed epitaxial Ge films were measured by the Fourier transform infrared spectrometer. The carrier concentration, mobility, resistivity, conductivity, and Hall coefficient of non-annealed and annealed epitaxial Ge films were also measured using the Hall effect device. The results show that the anneal treatment can improve the quality of epitaxial Ge films significantly. The absorption rate increases after anneal treatment and the transmittance in most area of epitaxial Ge film decreases dramatically. The transmittance decreases by 20% in the range of 615 to 3 730 cm^-1. The carrier concentration increases 22.26 times, and the carrier mobility increases 27.82 times after anneal treatment.