High Temperature Stability of PECVD Aluminium Oxide Layers Applied as Negatively Charged Passivation on c-Si Surfaces
Year: 2010
Type: conference-paper
Abstract: Plasma-enhanced chemical vapor deposited (PECVD) aluminum oxide (AlOx) layers were developed using a high-throughput industrial-type inline tool. The layers were investigated in order to receive high passivation quality and thermal stability. With these layers, serving as passivation of low resistivity p-type silicon surfaces, effective lifetimes of 2.3 ms (1 Ω·cm float-zone (FZ) silicon) could be achieved. The influence of different thermal treatments was studied, applying annealing in forming gas (FGA) and firing in a range of 350 °C to 900 °C. Different layer properties were investigated; appearance of blistering on the surface by means of scanning electron microscopy (SEM) measurements, electrical properties such as the fixed negative charge density Qf and the interface trap density Dit within the AlOx layer by means of capacitance-voltage (C-V) measurements. Firing resistant PECVD AlOx layers could be developed that show excellent passivation quality with Qf = -3.1·1012 cm-2 and Dit = 4·1010 cm-2 eV-1. Stack systems with an optional capping layer on top of the AlOx film, consisting of PECVD amorphous hydrogenated silicon nitride (a-SiNx:H), are presented as a solution for industrial screen printed silicon solar cells.
Institutions: University of Freiburg, Fraunhofer-Gesellschaft
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W192566747