Surface and bulk passivation of multicrystalline silicon solar cells by ...

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Figure 3.13 shows that: 1) after the firing, the majority of the surface damage is
healed; 2) Simultaneously, H migrates into bulk Si and interacts with defects and
impurities.
Α verification of H "storage" during nitridation and its subsequent diffusion is
seen in Figure 3.14 [98]. This figure is a secondary ion mass spectrometry (SIMS) plot of
H in a Si solar cell before and after annealing. Figure 3.14 clearly shows that the H is
temporarily stored at the surface, and is then redistributed (limited by the detection
sensitivity of H in the SIMS measurement) after annealing.
Figure 3.14 The SIMS profiles of H in a solar cell introduced during a PECVD SiN
coating before (red line) and after annealing (black line) [98].
The redistribution of H deep inside the cell can lead to excellent passivation and
high device performance. Figure 3.15 shows the difference in the poly-Si solar cell
performance with and without a PECVD SiN coating [99]. This exemplifies a significant
increase in efficiency. Α good hydrogenation process can improve the cell efficiency