Patent ID: 7247545
Filing Date: 2007-07-24
Classification: H01L

Abstract:
1. A method of fabricating a low defect germanium thin film, comprising: preparing a silicon wafer for germanium deposition; forming a germanium film using a two-step CVD process, wherein a first CVD step is performed at a temperature of between about 250° C. to 300° C., to form a continuous germanium film, and wherein a second CVD step is performed at a temperature of about 700° C., to form a relaxed germanium thin film; depositing a layer of germanium on the relaxed germanium thin film; annealing the germanium thin film using a multiple cycle process, wherein a first cycle is performed at a relatively higher temperature of between about 840° C. to 900° C., and a second cycle is performed at a relatively lower temperature of between about 750° C. to 840° C., and wherein the first and second cycles are alternately performed for between about 10 to 40 cycles to concentrate any defects in the germanium thin film in a region near the germanium/silicon interface; implanting hydrogen ions; depositing a layer of tetraethylorthosilicate oxide (TEOS); smoothing the TEOS layer by CMP; cleaning the TEOS layer; preparing a counter wafer; bonding the germanium thin film to the counter wafer to form a bonded structure; annealing the bonded structure at a temperature of at least 375° C. to facilitate splitting of the bonded wafer; splitting the bonded structure to expose the germanium thin film; removing any remaining silicon from the germanium thin film surface along with a portion of the germanium thin film defect zone; and incorporating the low-defect germanium thin film into the desired end-product device.