Analysis of dissolution and growth process of SiGe alloy semiconductor based on penetrated X-ray intensities

Si dissolution into Ge melt, solute transport in the Si–Ge solution and crystal growth of SiGe alloys were in situ observed by X-ray penetration method. The rectangular shaped sandwich sample of Si (seed)/Ge/Si (feed) was used for the experiment. X-ray intensities penetrated through the sample, which was heated up to the growth temperature of 1200 °C, were recorded by rectangular shaped CdTe line sensor as a function of time and temperature. The experimental results demonstrated that the dissolution of Si seed was larger compared to Si feed crystal although Si feed temperature was relatively higher than that of seed. Crystal growth of SiGe was observed at the feed interface as the growth interface was observed clearly by an abrupt change of penetrated X-ray intensity near the growth interface. Since the crystal grew with Si rich composition (at high temperature 1200 °C), solution becomes Ge richer which causes penetrated X-ray intensity variation at the growth interface. The growth mechanism for the observed SiGe growth process was discussed based on the penetrated X-ray intensity profile and a growth model. The composition of the grown sample was measured by FE-EPMA analysis.

• Dissolution process of Si seed and feed into Ge melt was in situ observed by X-ray penetration method.
• Composition profile of the Si–Ge solution was investigated from the penetrated X-ray intensity variations.
• Solute transport and crystal growth of SiGe was in situ observed and the possible growth mechanism was discussed.