Article contents
Gas Cluster Ge Infusion for Si(1−x)Ge(x)Strained-Layer Applications
Published online by Cambridge University Press: 01 February 2011
Abstract
Materials processing with a gas cluster ion beam (GCIB) is an emerging technology that has been shown to produce novel material properties in the very near-surface (<40nm) regime. We have termed the process of doping with GCIB, infusion. Its principal characteristic enables room temperature shallow processing with high concentration gradients and no sharp interfaces. Results are presented from an investigation of GCIB GeH4 infusion into Si(100) substrates for the purpose of producing a strained Si(1-x)Ge(x) layer relative to the Si substrate. The as-infused samples exhibit surface Ge concentrations up to 100%, with a steep concentration gradient over ∼40 nm. Specifically, a broad series of post-processing tube-furnace anneals was investigated over a temperature range of 400 °C to 1200 °C and the samples were analyzed by channeling/RBS to look at quality of recrystallization and for evidence of strain in the lattice. Some anneal schedules included a VLTA (very low temperature anneal) first step followed by subsequent HTA (high temperature anneal). Evidence is shown for improved results with no Ge loss using two-step anneals. Channeling analysis was performed along the <100> and <110> directions relative to the Si(100) substrate. Measurements of the min for both the Ge and Si were made to assess crystal quality and to determine the degree of epitaxial alignment with the Si lattice. High-resolution axial scans along <110> were performed on selected samples to look for strain relative to the Si lattice. SIMS analysis of higher temperature anneals showed significant diffusion of Ge. Some samples were also examined by cross-sectional TEM. The best infusion samples show crystal quality comparable to a commercially available epi-grown Si75Ge25 control sample.
- Type
- Research Article
- Information
- Copyright
- Copyright © Materials Research Society 2007
References
REFERENCES
- 1
- Cited by