In-situ characterization of a-Si:H devices during growth by microwave detected transient photoconductivity

The growth of n-i-p and p-i-n amorphous hydrogenated silicon structures, as used in solar cells, has been followed by measuring the transient photoconductivity with contactless microwave reflection measurements. The signals in p-layers are much lower than in intrinsic or n-type material due to the increased electron decay rate. Influences of a thin n- or p-layer on the transient photoconductivity signals during growth of a subsequently deposited intrinsic layer are discussed. The optical interference fringes can be used for in-situ determination of the deposition rate during growth.