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This thesis describes an experimental research on the HBT process that uses a SiGe epitaxy layer as its base, and also Ni based silicide for the high performance. The SiGe film was deposited at low temperature of 675~725 ℃ with various dielectric mask and process conditions using reduced pressure ch...

This thesis describes an experimental research on the HBT process that uses a SiGe epitaxy layer as its base, and also Ni based silicide for the high performance. The SiGe film was deposited at low temperature of 675~725 ℃ with various dielectric mask and process conditions using reduced pressure chemical vapor deposition. Pattern size and process conditions associated with the growth rate and Ge composition of theselective epitaxial growth (SEG) has been examined for the SiH4-GeH4-H2 system. The objective was to understand the effect of pattern size at low temperature for the feasible device applications. The growth rates showed large non-uniformity up to the ratio reaching 1.4 depending upon the pattern width of dielectric mask films. From the influence of the pattern shape/size and process parameters, the evolution of growth rates could be explained by the surface migration and the surface topology as well. After the surface migrationcontrol appearing dominantly at the initial stage, the surface topology became significant at the last part of the SEG process. The Ge composition is important to form the SEG, so that it is important to optimize the flow rate of SiH4, GeH4, and total source gas. We have studied thermo-electrical properties for Ni-based germanosilicide to understand the influence of temperature on the evolution of sheet resistance and micro structure of contacts on heavily doped SiGe grown by reduced pressure chemical vapor deposition. After the deposition of Ni, Ni/Ti, Ni/Pt films on Si0.83Ge0.17 epi layer and subsequently annealing for silicide reaction, we analyzed sheet resistance, surface roughness and reaction interfaces using four point probe method, scanning prove micrograph and transmission electron microscope. Bi-layer metal structure of Ni/Ti and Ni/Pt were investigated to study feasible use for suppressing inappropriate reaction at interface. It is found that bi-layer structure with thin Pt interlayer presented promising properties for germanosilicide of n+-Si0.83Ge0.17 with low sheet resistance, smooth surface morphology and high temperature stability up to 800 ℃.

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