Field effect (FE) a-Si:H solar cell promises an effective increase of conversion efficiency, respect to thin film p-i-n solar cells, by the use of an inversion layer at the cell surface obtained by FEs at amorphous silicon-insulator interface. In particular this structure avoids the presence of a p-doped window layer, which stems from the large absorption coefficient of a-Si:H. The window layer dramatically reduces cell efficiency. In this paper we present the first realization of a FE solar cell, based on the top channel configuration. Results on 0.25 and 1 cm(2) cells will be presented showing the FE collection mechanism and experimental comparison with usual p-i-n solar cell on transparent conductive oxide.