Comparative analysis of thermally induced degradation of condensation-grown (1 0 0)Ge_0.75Si_0.25/SiO₂ interfaces by electron spin resonance

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• 作者：J. Kepa ; A. Stesmans ; V.V. Afanas鈥檈v
• 关键词：Silicon&ndash ; germanium-on-insulator (SGOI) ; Silicon germanium alloys ; Electron spin resonance (ESR) ; Interface defects ; Pb type centers ; GePb1 defect ; High mobility transistors ; Thermal degradation
• 刊名：Applied Surface Science
• 出版年：1 February, 2014
• 年：2014
• 卷：291
• 期：Complete
• 页码：20-24
• 全文大小：602 K

文摘

An electron spin resonance study has been carried out on the influence of isochronal annealing on the GeSi/SiO₂ interfaces of the condensation grown (1 0 0)Si/SiO₂/Ge_0.75Si_0.25/SiO₂ structure. The thermal interface stability has been monitored in terms of the evolution of occurring paramagnetic interface defects, in particular, here involving the Ge dangling bond GeP_b1 point defect, previously identified as a detrimental interface trap. This reveals thermal post-growth interface degradation, initiating from annealing at the temperature 鈭?40 掳C onward, identified as substantial generation of GeP_b1 interface traps in addition to those naturally introduced into the system during sample manufacturing. In terms of GeP_b1 density, the interface thus appears only robust for thermal treatment in vacuum up to 440 掳C. For T_an reaching 鈭?20 掳C, a drastic degradation occurs as exposed by an about two-fold increase in GeP_b1 density, which state is maintained up to T_an 鈭?#xA0;900 掳C. Annealing in H₂ (鈭? atm) has a similar effect, except that the interface degrades more gradually. Above 900 掳C, the structure's integrity gradually collapses because of disintegration (Ge escape) of the SiGe layer. As to device implementation, the data indicate that temperatures of processing steps in O-deficient ambient should be kept below 鈭?40 掳C.