On the influence of ICP–PECVD deposition parameters and annealing on the properties of a–Si:H passivation layers

Hydrogenated amorphous silicon (a–Si:H) can be applied as a passivation layer in silicon heterojunction (SHJ) solar cells. In this project, depositions of a–Si:H thin films have been carried out using ICP–PECVD under several deposition conditions. This has been done to gain insight into the deposition process and how the properties of the deposited film can be controlled. To reach this goal, the deposition temperature, pressure and power have been varied to investigate the correlation between the plasma conditions and the properties of the deposited films. Also, an annealing series has been carried out to determine the influence of annealing on the properties of the a–Si:H film. The microstructure (i.e. porosity and hydrogen content) of the a–Si:H layers has been characterized by Raman spectroscopy, Fourier transformed infrared (FTIR) spectroscopy and spectroscopic ellipsometry (SE). By doing so, the influence of the deposition parameters and annealing on the properties of a–Si:H passivation layers has succesfully been determined.