The effects of interface properties such as a negative fixed charge density and an interface trap density on the surface passivation of crystalline Si by O3-based batch ALD AlOx were studied. High-quality surface passivation with Smax of ∼10cm/s was obtained from the AlO x samples deposited at 200 °C after annealing. This feature is attributed to the excellent field effect passivation by the high negative fixed charge density of ∼%5 ' 1012cm-2 and chemical passivation, which reduces the interface trap density to ∼1 ' 10 11 eV%1cm-2. The annealed AlOx samples deposited at 200 °C also show high thermal stability during firing at 850 °C. Additionally, we found that the formation of a thin SiOx interlayer is essential for the formation of a high negative fixed charge density that induces strong field effect passivation, and that defect passivation at the Si/SiOx interface by diffused hydrogen from AlOx layers is the origin of chemical passivation.
ASJC Scopus subject areas
- Physics and Astronomy(all)