Silicon-On-Diamond (SOD) technology has been proposed as an alternative Silicon-On-Insulator system, where the thermally insulating SiO2 is replaced by extremely thermally conductive diamond. Nevertheless fabrication of a suitable SOD material is still an issue. Growing diamond directly onto silicon by Chemical Vapour Deposition (CVD) leads to a defective interface while wafer bonding of silicon to diamond at high temperatures is limited by thermal mismatch between the two materials. We used the 355 nm radiation of a 20 ps pulsed laser to obtain continuous bonding between high quality polycrystalline diamond and monocrystalline silicon, at room temperature. The procedure has been carried out in a dedicated chamber, under uniaxial stress of the order of 100 MPa. The polished silicon and diamond surfaces have been previously characterized by optical profilometry in order to evaluate the pressure needed to obtain a good adhesion, which is critical to the outcome of the process. The formed silicon-diamond interface has been tested for thermal and mechanical stress, and for uniformity by scanning electron and atomic force microscopy, yielding good matching and adhesion between the two materials. Micro-Raman and FTIR spectroscopy show evidence of interface layers of SiC and amorphous silicon, whose thicknesses do not exceed 100nm.
Study of laser bonding of silicon to diamond for silicon-on-diamond (SOD) technology
SCORZONI, Andrea
2009
Abstract
Silicon-On-Diamond (SOD) technology has been proposed as an alternative Silicon-On-Insulator system, where the thermally insulating SiO2 is replaced by extremely thermally conductive diamond. Nevertheless fabrication of a suitable SOD material is still an issue. Growing diamond directly onto silicon by Chemical Vapour Deposition (CVD) leads to a defective interface while wafer bonding of silicon to diamond at high temperatures is limited by thermal mismatch between the two materials. We used the 355 nm radiation of a 20 ps pulsed laser to obtain continuous bonding between high quality polycrystalline diamond and monocrystalline silicon, at room temperature. The procedure has been carried out in a dedicated chamber, under uniaxial stress of the order of 100 MPa. The polished silicon and diamond surfaces have been previously characterized by optical profilometry in order to evaluate the pressure needed to obtain a good adhesion, which is critical to the outcome of the process. The formed silicon-diamond interface has been tested for thermal and mechanical stress, and for uniformity by scanning electron and atomic force microscopy, yielding good matching and adhesion between the two materials. Micro-Raman and FTIR spectroscopy show evidence of interface layers of SiC and amorphous silicon, whose thicknesses do not exceed 100nm.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
