Growth of hydrogenated amorphous silicon in a doping inversed silicon heterojunction solar cell (n-a-Si:H/i-a-Si:H/p-c-Si) interface was investigated by High Resolution Transmission Electron Microscopy (HR-TEM), Spectroscopic Ellipsometry (SE), Fourier Transform Infrared Attenuated Total Reflection spectroscopy (FTIR-ATR) and current-voltage (I-V) measurements. Effective Medium Approximation (EMA) to the SE was used to describe breakage of epi-Si and evolution of mixture of microcrystalline and amorphous phases. Fabricated silicon heterojunction solar cells were characterized by dark and light I-V measurements at Standard Test Conditions. By improving the cleaning and deposition conditions, solar cells with 9.2% efficiency over 72 cm(2) total active area were obtained on p-type c-Si wafers. (C) 2014 Elsevier Ltd. All rights reserved.