Low temperature exfoliation process in hydrogen-implanted germanium layers

作者：Ferain I P^*; Byun K Y; Colinge C A; Brightup S; Goorsky M S

来源：Journal of Applied Physics, 2010, 107(5): 054315.

DOI：10.1063/1.3326942

The feasibility of transferring hydrogen-implanted germanium to silicon with a reduced thermal budget is demonstrated. Germanium samples were implanted with a splitting dose of 5 x 10(16) H(2)(+) cm(-2) at 180 keV and a two-step anneal was performed. Surface roughness and x-ray diffraction pattern measurements, combined with cross-sectional TEM analysis of hydrogen-implanted germanium samples were carried out in order to understand the exfoliation mechanism as a function of the thermal budget. It is shown that the first anneal performed at low temperature (<= 150 degrees C for 22 h) enhances the nucleation of hydrogen platelets significantly. The second anneal is performed at 300 degrees C for 5 min and is shown to complete the exfoliation process by triggering the formation of extended platelets. Two key results are highlighted: (i) in a reduced thermal budget approach, the transfer of hydrogen-implanted germanium is found to follow a mechanism similar to the transfer of hydrogen-implanted InP and GaAs, (ii) such a low thermal budget (<300 degrees C) is found to be suitable for directly bonded heterogeneous substrates, such as germanium bonded to silicon, where different thermal expansion coefficients are involved.

• 出版日期2010-3-1