SOI/bulk hybrid wafer fabrication process using selective epitaxial growth (SEG) technique for high-end SoC applications

The size of SiN region and the growth condition were investigated for the robust process of selective epitaxial growth for the fabrication of the silicon on insulator (SOI)/bulk hybrid wafer. Silicon nucleation on SiN layer was observed during the selective epitaxial growth process using SiH2Cl2/HCl/H-2 mixture at 1000-1100degreesC. At the center of SiN region, the coverage of SiN region by nucleated silicon increases With the increase of growth rate of epitaxial silicon layer, deposition time and the size of SiN region. At the edge of SiN region, there are nucleation-free regions. Also, silicon nucleation on SiN layer has an incubation time. The incubation time increases with the decrease of the size of SiN region. The incubation time for SiN region which has rectangular shape is longer than that for SiN region of square shape which has the same area. Under the condition which has the same growth rate regardless of the deposition temperature, there is an optimum temperature for suppression of silicon nucleation on SiN layer. These facts mean that the size of the SiN cap layer of SOI region should be decided carefully for the fabrication of SOI/bulk hybrid wafer by the selective epitaxial growth method.