Investigation of Field-Effect Passivation Created by Hydrogen Plasma Etching of Radio Corporation of America Formed Chemical Oxides on Crystalline Silicon Wafers
Investigation of Field-Effect Passivation Created by Hydrogen Plasma Etching of Radio Corporation of America Formed Chemical Oxides on Crystalline Silicon Wafers
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美国无线电公司晶硅片上化学氧化物氢等离子体刻蚀场效应钝化研究
DOI：
10.1002/pssa.202000586
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发表时间：
2021
影响因子：
2
通讯作者：
Ge Jia
中科院分区：
文献类型：
--
作者：
Jia Haitian;Tang Muzhi;Ge Jia
本工作研究了本征氢化非晶硅薄膜钝化晶片经氢等离子体清洗后的界面特性。研究发现，接近-0.6 eV的高水平界面能带弯曲（对应于-2.2 × 1012 cm-2的固定电荷）是4.5 Ω cm n型晶片上有效少数载流子寿命超过6 ms的原因，而这种场效应钝化在氢氟酸（HF）清洁的晶片中缺失。进一步的研究表明，表面能带弯曲的程度和掺杂浓度之间的正相关性，以及相对于增加的退火条件的倒U形。发现p型晶片上的固定电荷与n型情况相比具有更高的“形成能”，这使得其场效应钝化由于在高退火温度下的H渗出而变得不那么有效。参考H等离子体处理时施主/受主-H络合物的理论，讨论了两种掺杂剂类型的表面能带弯曲的起源和观察到的性质。氢等离子体清洗的n型晶片上独特的场效应可以为异质结硅晶片太阳能电池的钝化材料选择和结构设计提供新的见解。
This work investigates the interface properties of intrinsic hydrogenated amorphous silicon film passivated wafers that underwent hydrogen plasma cleaning. A high level of interface band bending of nearly −0.6 eV, which corresponds to a fixed charge of −2.2 × 1012cm−2, is found to be responsible for an effective minority carrier lifetime of over 6 ms on the 4.5 Ω cm n‐type wafer, while such field‐effect passivation is missing in hydrofluoric acid (HF) cleaned wafers. Further study indicates a positive correlation between the extent of surface band bending and doping concentration, together with an inverted U‐shape with respect to the increased annealing condition. The fixed charge on p‐type wafer is found to have a higher “formation energy” compared with the n‐type case, which renders its field‐effect passivation much less effective due to H effusion at high annealing temperatures. With reference to the theory on donor/acceptor‐H complex upon H plasma treatment, the origin and observed properties of the surface band bending on both dopant types are discussed. The unique presence of field effect on hydrogen plasma cleaned n‐type wafers can provide new insights into passivation material selection and structural design of heterojunction silicon wafer solar cells.