Thermal and mechanical separations of silicon layers from hydrogen pattern-implanted wafers

A silicon layer was successfully transferred from a hydrogen pattern-implan ted wafer to another by a thermal or mechanical cleavage process. The first wafer was masked with various patterns of 2.3 micron-thick poly-silicon, a nd was implanted at a hydrogen dose of 4, 5, or 8 X 10(16) cm(-2) with an e nergy of 150 keV or 180 keV. After etching off the implantation mask, the w afer was bonded to a thermally grown oxide wafer face-to-face by low-temper ature direct bonding. The bonded pair was then either heated (thermally) or bent (mechanically) until hydrogen-induced silicon layer cleavage occurred , resulting in the silicon layer transfer from the implanted wafer to the o ther. In this experiment, it was demonstrated that mechanical cleavage can overcome the fractional implantation area limitation of thermal cleavage.