Effect of Si Content in AlSi Local Rear Contacts of n-PERT Solar Cells on the Al-p+ Junction Formation

This works investigates the effect of Si content on the Al-p+ junction formation on the AlSi local rear contacts for the n-PERT Si solar cells. For this, the Al paste was modified by adding Si powder with content up to 6%wt. After that, the prepared Al-Si pastes were screen- printed on the n-type Si wafers. The Al-Si pastes were then fired in RTP furnace at a set peak temperature of 783 °C under N2 atmosphere to form the AlSi local rear contacts. The Al-Si pastes were then examined using the optical microscope, Scanning Electronic Microscopy (SEM) and the X-ray diffraction. The results showed that the added Si powder affected the properties of the Al-p+ junction as well as the Al-Si eutectic layer between the Al-p+ junction and the AlSi local rear contacts.