Conventional dopant diffusion technique has been successfully employed to dope SiGe films deposited by ion-beam sputtering (IBS). The deposited a-SiGe films can be doped to both p and n types after boron and phosphorous diffusions at a temperature range of 850-1000℃. The doping process is accompanied by crystallization of the a-SiGe film. Electrical properties of the doped SiGe films have been characterized by a four-point probe and Hall measurements. Hall mobilities as high as 13 and 31cm2/V·s have been obtained in boron-and phosphorous-doped polycrystalline SiGe films, respectively.

The temperature-dependent current-voltage (I-V-T) technique has been used to study the Ni/Si solid phase reaction by measuring the Schottky barrier height (SBH) inhomogeneity of Ni-silicide/Si Schottky diodes. The experimental results show the strong dependence of SBH inhomogeneity on the Ni/Si solid phase reaction. The SBH distribution of the diodes annealed at 500 and 600℃ can be described by a single-Gaussian function and the diode annealed at 500℃ is found to have the best homogeneity and the smallest leakage current. The SBH distribution of the diodes annealed at 400, 700, and 800℃ can be described by a double-Gaussian function in which the mean value of the second Gaussian function is substantially smaller than that of the dominant Gaussian function. The variation of SBH inhomogeneity, an interface property, is related to the phase evolution process in the Ni/Si solid phase reaction, and verified by reverse I-V measurements. Our results indicate that the I-V-T technique may be developed as a wafer-level testing tool to monitor the silicidation process in the complementary metal-oxide-semiconductor device fabrication.

Schottky and pn junction diodes with good rectifying characteristics have been prepared based on the polycrystalline SiGe (poly-SiGe) thin film deposited by the ion-beam-sputtering (IBS) technique. Boron and phosphorus diffusion techniques have been used to dope and crystallize as-deposited amorphous SiGe film. Rectification ratios as high as 4000 and 1800 have been achieved in Pt/n-poly-SiGe and Ti/p-poly-SiGe Schottky diodes, respectively, while rectification ratio higher than 1500 and breakdown voltage higher than 200V have been achieved in poly-SiGe pn junction diodes. Schottky barrier height has been determined to be 0.62 and 0.59 eV for Pt/n-poly-Si0.81Ge0.19 and Ti/p-poly-Si0.81Ge0.19 contacts, respectively, which indicates that the band alignment of poly-SiGe may be substantially different from that of epitaxial SiGe.

讨论了半导体pn结内建电场和接触电势的形成与可测性，回答了在半导体物理学pn结内容教学中学生经常会提出的一个似是而非的问题。从热力学第一定律、金属-半导体接触等不同角度详细解释了热平衡（零偏下）时pn结不可能对外输出电压和电流的原因。

Amorphous Si0.87Ge0.13 is deposited on n-Si (100) substrate by ion beam sputtering (IBS) and doped through thermal diffusion of phosphorus to fabricate n-poly-Si0.87Ge0.13 thin film. The formation of Schottky junction is made by deposition Ni on n-poly-Si0.87Ge0.13 by IBS. Solid-phase reaction mainly occurred above 400℃ by rapid thermal annealing at the interface of Ni/n-poly-Si0.87Ge0.13. Phase identification and depth profile were investigated by X-ray diffraction (XRD) and Auger electron spectroscopy (AES), respectively. The electrical properties of both unannealed and annealed Ni/n-poly-Si0.87Ge0.13 were studied by current-voltage (I-V) measurement. The results demonstrate that the Schottky barrier height (SBH) changes little with the annealing temperature between 300 and 600℃. The constancy of SBH is attributed to the properties of the interface itself which determine the SBH and substantially independent of whether the interfacial material is nickel or nickel germanosilicide.