1. Comparison of firing stability between p‐ and n‐type polysilicon passivating contacts.
- Author
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Kang, Di, Sio, Hang Cheong, Stuckelberger, Josua, Yan, Di, Phang, Sieu Pheng, Liu, Rong, Truong, Thien N., Le, Tien, Nguyen, Hieu T., Zhang, Xinyu, and Macdonald, Daniel
- Subjects
POLYCRYSTALLINE silicon ,SECONDARY ion mass spectrometry - Abstract
This work compares the firing response of ex‐situ doped p‐ and n‐type polysilicon (poly‐Si) passivating contacts and identifies possible mechanisms underlying their distinct firing behavior. The p‐type poly‐Si shows greater firing stability than n‐type poly‐Si, particularly at a higher firing temperature, which results in a substantial increase in the recombination current density parameter J0 from 9 to 96 fA/cm2 upon firing at 900°C for n‐type poly‐Si, in comparison to an increase from 11 to 30 fA/cm2 for p‐type poly‐Si. It is observed that p‐type poly‐Si contacts only suffer a slight degradation or even exhibit a small improvement in J0 after firing at 800°C, depending on the boron diffusion temperature. Secondary ion mass spectrometry (SIMS) results demonstrate that the hydrogen concentration near the interfacial SiOx increases with the peak firing temperature in n‐type poly‐Si, whereas the hydrogen profile remains unchanged for p‐type poly‐Si upon firing at various temperatures. Moreover, we observe that injecting additional hydrogen into the poly‐Si/SiOx stacks fired with SiNx coating layers further degrades n‐type poly‐Si, but recovers the J0 of p‐type poly‐Si to the value before firing. In contrast, removing hydrogen from the fired poly‐Si/SiOx stacks leads to an initial recovery and then a second degradation of J0 in n‐type poly‐Si, but no substantial impact on p‐type poly‐Si. It is hypothesized that the distinct difference in the firing impact on p‐ and n‐type poly‐Si is related to the different effective hydrogen diffusivity, which determines the hydrogen content surrounding the SiOx layer and hence the passivation quality after firing. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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