LAYER TRANSFER AND CHARACTERIZATION OF SOI AND GeOI SUBSTRATES

摘要

Layer transfer of SOI and GeOI substrates have been realized by ion-cut processes. 40keV H~+ were implanted to Ge and SiO_2/Si donor wafers to three doses, 2, 4, 6x10~(16)/cm~2, and acceptor wafers are Si_3N_4/Si and SiO_2/Si. For the dose of 6x10~(16)/cm~2, large area Ge layer with 400nm thickness can be transferred on Si_3N_4/Si acceptor wafer by mechanical-cut at 205℃. Thermal-cut can be done at 270℃ or higher. The GeOI transferred thickness is distinctly larger than the predicted H-peak depth by SRIM. Comparing with the RMS value 7.5nm of SOI surface, GeOI has much larger value of about 20nm. Differential Hall measurement was used to characterize the electrical properties of mechanically-cut GeOI with various annealing temperature up to 800℃. Hall data show mobility is comparable to that of Ge donor wafer for GeOI thicker than 182nm but it dramatically drops near bonding interface. The current results suggest bonding interface is a major concern for functional GeOI substrates.