Diffusion versus oxidation rates in silicon‐germanium alloys
Diffusion versus oxidation rates in silicon‐germanium alloys
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硅锗合金中的扩散与氧化速率
DOI：
10.1063/1.105528
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发表时间：
1991
影响因子：
4
通讯作者：
F. d'Heurle
中科院分区：
文献类型：
--
作者：
J. Eugène;F. Legoues;V. Kesan;S. Iyer;F. d'Heurle
我们研究了不同成分(25~75at.%Ge)的SiGe合金的氧化行为。在分子束外延生长的7500A厚的薄膜上，所有的氧化都是在90 0 °C的湿空气中进行的。在50at.%Ge以下，氧化保持与前面描述的相似，即，最初，Ge的存在提高了氧化速率，形成的氧化物是纯SiO_2，并且在SiO_2/Si-Ge界面处形成Ge堆积。在这些相对较厚的薄膜中，我们认为在延长氧化后，界面硅浓度的降低足以减缓氧化速度，从而最终使SiGe合金的氧化层厚度小于纯Si的氧化层厚度。对于Ge含量在50at.%以上的合金，发现了明显不同的行为：形成了两层氧化物，由接近表面的混合(Si，Ge)O2层和下面的纯SiO_2层组成。这种情况下的氧化速度甚至更快，因为Ge和Si都被氧化了。一般行为..。
We have studied the oxidation of SiGe alloys of different compositions (between 25 and 75 at.% Ge). All of the oxidations were performed at 900 °C in wet atmosphere on 7500‐A‐thick films grown by molecular beam epitaxy. Below 50 at.% Ge, the oxidation remains similar to what has been described previously, i.e., initially, the rate is enhanced by the presence of Ge, the oxide formed is pure SiO2 and a Ge pileup forms at the SiO2/Si‐Ge interface. In these relatively thick films, we propose that after extended oxidation, the decrease of Si concentration at the interface slows down oxidation rates enough so that eventually, the oxide thickness for the SiGe alloys ends up smaller than that of pure Si. For alloys containing above 50 at.% Ge, a markedly different behavior is found: A two‐layer oxide is formed, consisting of a mixed (Si,Ge) O2 layer near the surface, and a pure SiO2 layer underneath. The rates of oxidation in this case are even faster, since both Ge and Si are being oxidized. The general behavior...