Polysilicon deposition process parameters have been addressed for the preparation of poly layers having characteristics that increase extrinsic gettering behaviour, irrespective of oxygen enhanced precipitation, thus making them particularly suitable for relatively high device processing temperatures.

Morphological parameters that correlate with extrinsic gettering efficiency have been found to be grain sizes and their preferred orientation, so care was given to produce and consistently reproduce such characteristics by a suitable choice of the deposition process parameters.