Tensile strained Ge quantum wells on Si substrate: Post-growth annealing versus low temperature re-growth

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• 作者：M.J. Sü ; ess^a ; ^b ; ^d ; ^{martin.sueess@emez.ethz.ch} ; L. Carroll^a ; H. Sigg^a ; A. Diaz^a ; D. Chrastina^c ; G. Isella^c ; E. Mü ; ller^b ; R. Spolenak^d
• 关键词：BT ; Brewster transmission ; DG ; direct-gap ; HH ; Heavy hole ; HRXRD ; high-resolution X-ray diffraction ; LH ; Light hole ; LEPECVD ; low-energy plasma-enhanced chemical vapor deposition ; MQW ; multiple quantum well ; PECVD ; plasma-enhanced chemical vapor depositio
• 刊名：Materials Science and Engineering ; B
• 出版年：2012
• 期刊代码：76_09215107
• 类别：ch
• 出版时间：5 June, 2012
• 卷：177
• 期：10
• 页码：696-699
• 文件大小：668 K

摘要

We investigate tensile strained Ge/Si_{1 鈭?#xA0;x}Ge_x (x = 0.87) multiple quantum wells (MQW) on a Ge virtual substrate abruptly grown on Si for integration in CMOS technology. Two schemes are discussed - Scheme A in situ growth of the MQW stack combined with post-growth rapid thermal annealing (RTA) and Scheme B re-growth of the MQW stack on an RTA strain optimized Ge-VS. Samples are characterized by Raman spectroscopy, X-ray diffraction (XRD), scanning transmission electron microscopy, Brewster transmission and photo-reflectance spectroscopy. The strain in the as-grown virtual substrate of Scheme A, measured with Raman spectroscopy and XRD, increases from 0.17%to 0.24%after RTA to 850 掳C. XRD reveals an activated inter-diffusion of the MQWs and, at the highest temperatures (T_RTA > 750 掳C), a structural relaxation. The MQWs of Scheme B appear to be of inferior quality. The inter-band transitions in this material are comparatively blue shifted and broad, which is attributed to relaxation induced dislocations at the interface between the virtual substrate and the multiple quantum wells.