Very shallow p~+ junctions (lower than 60 nm) have been fabricated by implanting Sb and subsequently BF_2, at a higher dose, in a n-type Si substrate. The pramorphisation with Sb avoids the B channeling and increases the n-type doping in the junction region, thus confining the depth of the p layer. Furthermore, both the transient enhanced diffusion, being the B implanted in a preamorphized layer, and the standard diffusion, due to the pairing between donors and acceptors, are strongly reduced. This procedure allows us to obtain very shallow junctions even after annealings with relatively high thermal budget, like 800 C/8h, or 900 C/1h, or 8950 C/15min or 1000 C/60s. Dopant diffusion is strongly affected by the direct donor-acceptor interaction. Good agreement between experimental and simulation results can only be obtained using a simulation code which takes into account the formation of neutral, near immobile, Sb-B pairs.
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机译:通过以较高的剂量将Sb和随后的BF_2注入到n型Si衬底中,已经制造出非常浅的p〜+ / n结(低于60 nm)。 Sb的过晶化避免了B沟道,并增加了结区中的n型掺杂,从而限制了p层的深度。此外,由于施主和受主之间的配对而导致的瞬态增强扩散(即注入预非晶化层中的B)和标准扩散均被大大降低。即使在以相对较高的热预算进行退火之后,例如800 C / 8h或900 C / 1h或8950 C / 15min或1000 C / 60s,此过程也使我们可以获得非常浅的结。掺杂剂的扩散受直接的供体-受体相互作用强烈影响。实验和模拟结果之间的良好一致性只能使用模拟代码获得,该代码考虑了中性,接近固定的Sb-B对的形成。
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