Effect of substrate growth temperatures on H diffusion in hydrogenated Si∕Si homoepitaxial structures grown by molecular beam epitaxy

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We have studied hydrogen diffusion in plasma hydrogenated Si∕SiGe∕Si heterostructure at different temperatures. At low temperature, intrinsic point defects in the molecular beam epitaxy grown Si capping layer are found to compete with the buried strain SiGe layer for hydrogen trapping. The interaction of hydrogen with point defects affects the hydrogen long-range diffusion, and restricts the amount of hydrogen available for trapping by the SiGe layer. However, hydrogen trapping by the capping layer is attenuated with increasing hydrogenation temperature allowing more hydrogen to be trapped in the strain SiGe layer with subsequent surface blister formation. A potential temperature window for plasma hydrogenation induced layer separation is identified based on the combined considerations of trap-limited diffusion at low temperature and outdiffusion of H2 molecule together with the dissociation of Si–H bonds inside of H platelet at high temperature.

mentioning

confidence: 99%

Effect of temperature on layer separation by plasma hydrogenation

Wang

Nastasi

et al. 2008

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“…5 In this situation, the trapped H peak concentration at the Si/ Si interface was 1 ϫ 10 20 cm −3 , an order of magnitude less than that shown in Fig. 5 In this situation, the trapped H peak concentration at the Si/ Si interface was 1 ϫ 10 20 cm −3 , an order of magnitude less than that shown in Fig.…”

mentioning

confidence: 74%

The role of strain in hydrogenation induced cracking in Si∕Si1−xGex∕Si structures

Shao

Lin

et al. 2008

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Hydrogenation induced cracking in molecular beam epitaxy grown Si∕Si1−xGex∕Si heterostructures is studied. The Si1−xGex layer buried between an ∼200nm thick Si capping layer and the Si substrate is ∼5nm thick. After plasma hydrogenation, long range H migration and H trapping at the Si1−xGex layer are observed. With increasing Ge concentrations, the amount of H trapping increases, cracking along the Si1−xGex layer is smoother, and fewer defects are formed in the Si capping layer. The study suggests maximizing the interfacial strain to achieve the smoothest cracking with minimized radiation damage for ultrathin silicon-on-insulator technology.

Cracking in hydrogen ion-implanted Si∕Si0.8Ge0.2∕Si heterostructures

Shao

Wang

Swadener

et al. 2008

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We demonstrate that a controllable cracking can be realized in Si with a buried strain layer when hydrogen is introduced using traditional H-ion implantation techniques. However, H stimulated cracking is dependent on H projected ranges; cracking occurs along a Si0.8Ge0.2 strain layer only if the H projected range is shallower than the depth of the strained layer. The absence of cracking for H ranges deeper than the strain layer is attributed to ion-irradiation induced strain relaxation, which is confirmed by Rutherford-backscattering-spectrometry channeling angular scans. The study reveals the importance of strain in initializing continuous cracking with extremely low H concentrations.