Invited Strain Engineering for SiGe Buffer Layers for High-Mobility Si Channels (先端デバイスの基礎と応用に関するアジアワークショップ(AWAD2005))

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Strain and dislocation engineering for the growth of high quality hetero-epitaxial films is crucial for realizing high performance heterostructure-based electronic and opto-electronic devices. Here we demonstrate two novel epitaxial growth processes of strain-relaxed SiGe films on Si(001) substrates, both of which have potential to be applied to the growth of buffer layers in strained channel metal-oxide-semiconductor field effect transistors. Two-step strain relaxation procedure has realized considerably high degree of strain relaxation in spite of total film thickness less than 200nm. This procedure greatly suppresses the pile-up of misfit dislocations and creates a characteristic dislocation morphology in which dislocations exist dispersively at the first SiGe/Si substrate interface. We have also developed a method to form SiGe buffer layers by solid-phase intermixing of Ge and deposited-Si layers at high temperatures. In this case, strain in SiGe is relaxed predominantly by the pure-edge dislocation network buried at the SiGe/Si(001) interface. Thin SiGe buffer layers with reduced mosaicity and flat surface morphology can be obtained. Strain relaxation mechanisms from a viewpoint of dislocation behavior in the film are discussed.
社団法人電子情報通信学会の論文
2005-06-23