Depth-profiling of implanted Si-28 by (alpha,alpha) and (alpha,p(0)) reactions

作者：Demarche J^*; Yedji M; Terwagne G

来源：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms , 2010, 268(11-12): 2107-2110.

DOI：10.1016/j.nimb.2010.02.061

• Silicon
• Nuclear reaction
• Resonance
• Backscattering
• Depth-profiling

Silicon nanocrystals enclosed in thin films (Si quantum dots or Si QDs) are regarded to be the cornerstone of future developments in new memory, photovoltaic and optoelectronic products. One way to synthesize these Si QDs is ion implantation in SiO2 layers followed by thermal annealing post-treatment.
Depth-profiling of these implanted Si ions can be performed by reactions induced by alpha-particles on Si-28. Indeed, for high incident energy, nuclear levels of S-32 and P-31 can be reached, and cross-sections for (alpha,alpha) and (alpha,p(0)) reactions are more intense. This can help to increase the signal for surface silicon, and therefore make distinguishing more easy between implanted Si and Si coming from the SiO2, even for low fluences.
In this work, (alpha,alpha) and (alpha,p(0)) reactions are applied to study depth distributions of 70 key Si-28(+) ions implanted in 200 nm SiO2 layers with fluences of 1 x 10(17) and 2 x 10(17) cm(-2). Analysis is performed above E-R = 3864 keV to take advantage of resonances in both (alpha,alpha) and (alpha,p(0)) cross-sections. We show how (alpha,p(0)) reactions can complement results provided by resonant backscattering measurements in this complex case.

• 出版日期2010-6