Focused ion beam implantation of Ga in Si and Ge: fluence‐dependent retention and surface morphology
Focused ion beam implantation of Ga in Si and Ge: fluence‐dependent retention and surface morphology
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DOI：
10.1002/sia.2915
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发表时间：
2008-11
影响因子：
1.7
通讯作者：
H. Gnaser;A. Brodyanski;B. Reuscher
中科院分区：
文献类型：
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作者：
H. Gnaser;A. Brodyanski;B. Reuscher
用SIMS研究了30 keV的Ga+离子在单晶Si和Ge中的聚焦离子束注入，Cs+原初离子溅射。植入面积为40 × 40µm2，植入影响范围为1 × 1013 ~ 1 × 1017 Ga+ ions/cm2，共9种。通过SIMS深度谱分析确定了这些植入物的Ga浓度分布。这种30 keV的Ga注入也通过动态蒙特卡罗代码进行了模拟，该代码考虑了由于Ga加入而导致的近表面成分的逐渐变化。在这两种方法中，Ga峰浓度随通量的增加基本上呈线性增加，可达~ 1 × 1016cm−2；对于较高的影响，Ga含量接近饱和水平，达到约（1-2）× 1017cm−2。实测和模拟的Ga分布峰浓度吻合较好。从实验中得到的最可能的范围与模拟的各自值非常接近。利用原子力显微镜（AFM）研究了Ga+注入引起的表面形貌。AFM数据表明，对于低影响（<3 × 1015cm−2），植入区域内的表面向外生长（即肿胀）。对于越来越高的影响，溅射引起的表面侵蚀成为主要因素，在1 × 1016cm−2以上的影响会形成明显的陨石坑。在注入区边界，发现在注入后形成一个壁状结构；它的高度随着通量的增加而增加，在1 × 1017 Ga+离子/cm2时达到约15 nm。版权所有©2008 John Wiley & Sons， Ltd
Focused ion beam implantation of 30‐keV Ga+ ions in single‐crystalline Si and Ge was investigated by SIMS, using Cs+ primary ions for sputtering. Nine different implantation fluences ranging from 1 × 1013 to 1 × 1017 Ga+‐ions/cm2 were used, with implanted areas of 40 × 40 µm2. The Ga concentration distributions of these implants were determined by SIMS depth profiling. Such 30‐keV Ga implantations were also simulated by a dynamic Monte‐Carlo code that takes into account the gradual change of the near‐surface composition due to the Ga incorporation. In both approaches, an essentially linear increase of the Ga peak concentrations with fluence is found up to ∼1 × 1016cm−2; for higher fluences, the Ga content approaches a saturation level which is reached at about (1–2) × 1017cm−2. The measured and simulated peak concentrations of the Ga distributions are in good agreement. The most probable ranges obtained from the experiments correspond closely with the respective values from the simulations. The surface morphology caused by Ga+ implantation was investigated by atomic force microscopy (AFM). The AFM data indicate that for low fluences (<3 × 1015cm−2) the surface within the implanted areas is growing outward (i.e. is swelling). For increasingly higher fluences, sputter‐induced erosion of the surface becomes dominant and distinct craters are formed for fluences above ∼1 × 1016cm−2. At the boundary of the implanted region a wall‐like structure is found to form upon Ga implantation; its height is growing with increasing fluence, reaching a value of ∼15 nm at 1 × 1017 Ga+‐ions/cm2. Copyright © 2008 John Wiley & Sons, Ltd.