Evolution of silicon bulk lifetime during III–V‐on‐Si multijunction solar cell epitaxial growth
Evolution of silicon bulk lifetime during III–V‐on‐Si multijunction solar cell epitaxial growth
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III-V-on-Si 多结太阳能电池外延生长过程中硅体寿命的演变
DOI：
10.1002/pip.2703
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
S. Ringel
中科院分区：
文献类型：
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作者：
E. García;J. Carlin;T. Grassman;D. Martín;I. Rey‐Stolle;S. Ringel
分析了通过金属有机化学气相沉积（MOCVD）在Si上异质外延生长III-V族多结太阳能电池结构期间Si体少数载流子寿命的演变。特别地，研究了在整个基于MOCVD的III-V/Si生长过程中的四个不同阶段对Si寿命的影响：（1）Si同质外延发射极/帽层;（2）GaP异质外延成核;（3）体GaP膜生长;以及（4）厚GaAsyP 1-y组分渐变变质缓冲生长。在阶段1（Si同质外延）期间，观察到Si少数载流子寿命降低了约两个数量级，从约450降至≤1 µs。然而，差距成核（阶段2）和较厚的膜（阶段3）生长之后，发现寿命增加了约一个数量级。然后发现厚的GaAsyP 1-y梯度缓冲液提供进一步恢复到初始起始值附近。观察到的寿命演变背后最可能的一般机制如下：由于在Si块体内形成热致缺陷，Si同质外延期间的寿命退化，随后的寿命恢复是由于在III-V生长期间来自前体热解的快速扩散原子氢，特别是V族元素（PH 3，AsH 3）的钝化。这些结果表明，用于产生这些目标III-V/Si太阳能电池结构的MOCVD生长方法对Si衬底内的少数载流子寿命具有实质性和动态的影响。版权所有© 2015约翰威利父子有限公司.
The evolution of Si bulk minority carrier lifetime during the heteroepitaxial growth of III–V on Si multijunction solar cell structures via metal‐organic chemical vapor deposition (MOCVD) has been analyzed. In particular, the impact on Si lifetime resulting from the four distinct phases within the overall MOCVD‐based III–V/Si growth process were studied: (1) the Si homoepitaxial emitter/cap layer; (2) GaP heteroepitaxial nucleation; (3) bulk GaP film growth; and (4) thick GaAsyP1‐y compositionally graded metamorphic buffer growth. During Phase 1 (Si homoepitaxy), an approximately two order of magnitude reduction in the Si minority carrier lifetime was observed, from about 450 to ≤1 µs. However, following the GaP nucleation (Phase 2) and thicker film (Phase 3) growths, the lifetime was found to increase by about an order of magnitude. The thick GaAsyP1‐y graded buffer was then found to provide further recovery back to around the initial starting value. The most likely general mechanism behind the observed lifetime evolution is as follows: lifetime degradation during Si homoepitaxy because of the formation of thermally induced defects within the Si bulk, with subsequent lifetime recovery due to passivation by fast‐diffusing atomic hydrogen coming from precursor pyrolysis, especially the group‐V hydrides (PH3, AsH3), during the III–V growth. These results indicate that the MOCVD growth methodology used to create these target III–V/Si solar cell structures has a substantial and dynamic impact on the minority carrier lifetime within the Si substrate. Copyright © 2015 John Wiley & Sons, Ltd.