Optimum Hydrogen Injection in Phosphorus-Doped Polysilicon Passivating Contacts.
Optimum Hydrogen Injection in Phosphorus-Doped Polysilicon Passivating Contacts.
复制标题
磷掺杂多晶硅钝化触点中的最佳注氢。
DOI：
10.1021/acsami.1c17342
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发表时间：
2021
影响因子：
9.5
通讯作者：
D. Macdonald
中科院分区：
文献类型：
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作者：
D. Kang;H. Sio;J. Stuckelberger;Rong Liu;D. Yan;Xinyu Zhang;D. Macdonald
先前已经示出，氧化硅上的非原位磷掺杂多晶硅（poly-Si/SiOx）钝化触点在经受800 °C或更高温度下的烧制处理时可能遭受显著的表面钝化退化。降解行为强烈地依赖于处理条件，例如介电涂层和烧制温度。目前的工作进一步研究了多晶硅接触的烧制稳定性，并提出了一种基于氢的作用的观察到的行为的机制。应用二次离子质谱法测量在不同温度下烧制后以及通过在氮气中退火去除氢后多晶Si/SiOx结构中的氢浓度。虽然已知界面SiOx周围的一定量的氢可有益于钝化，但令人惊讶的是，我们发现过量的氢可使多晶硅钝化劣化并增加复合电流密度参数J 0。过量氢的存在在用氮化硅（SiNx）烧制的所选多晶硅样品中是明显的，其中向SiOx夹层注入额外的氢导致J 0的进一步退化，而去除氢完全恢复表面钝化。此外，所提出的模型解释了依赖于焙烧稳定性的微晶性质和掺杂的档案，这决定了有效的扩散率的氢在焙烧后，因此周围的界面氧化硅焙烧后的氢的量。
It has previously been shown that ex situ phosphorus-doped polycrystalline silicon on silicon oxide (poly-Si/SiOx) passivating contacts can suffer a pronounced surface passivation degradation when subjected to a firing treatment at 800 °C or above. The degradation behavior depends strongly on the processing conditions, such as the dielectric coating layers and the firing temperature. The current work further studies the firing stability of poly-Si contacts and proposes a mechanism for the observed behavior based on the role of hydrogen. Secondary ion mass spectrometry is applied to measure the hydrogen concentration in the poly-Si/SiOx structures after firing at different temperatures and after removing hydrogen by an anneal in nitrogen. While it is known that a certain amount of hydrogen around the interfacial SiOx can be beneficial for passivation, surprisingly, we found that the excess amount of hydrogen can deteriorate the poly-Si passivation and increase the recombination current density parameter J0. The presence of excess hydrogen is evident in selected poly-Si samples fired with silicon nitride (SiNx), where the injection of additional hydrogen to the SiOx interlayer leads to further degradation in the J0, while removing hydrogen fully recovers the surface passivation. In addition, the proposed model explains the dependence of firing stability on the crystallite properties and the doping profile, which determine the effective diffusivity of hydrogen upon firing and hence the amount of hydrogen around the interfacial SiOx after firing.