Carrier lifetime axial adjustment in semiconductor - by impurity diffusion, irradiation and thermal de-activation

摘要

Axial adjustment of carrier lifetime in a semiconductor device with a crystalline semiconductor substrate is carried out by (a) diffusion into the substrate, of impurity atoms which are inert w.r.t. recombination at lattice site and are active w.r.t. recombination at interstitial sites and which diffuse interstitially and via. the vacancy mechanism but not by the kick-out mechanism, (b) irradiation of the substrate with high energy heavy particles so that a desired concn. profile of radiation defects is produced to a predetermined depth, and (c) thermal de-activation of the diffused impurity atoms in any substrate region, in which the desired cocn. profile of radiation defects is provided. ADVANTAGE - Both the properties of the recombiantion centres and the associated concn. profile can be relatively freely selected.