AUTOMATED LIFETIME MONITORING FOR FACTORY PROCESS-CONTROL

A methodology is described for using automated lifetime measurements a s a diagnostic tool and process monitor in the fabrication of HgCdTe d etectors. The influence of background flux on the accuracy of these me asurements is quantified using a new high-level injection model. Autom ated lifetime testing, applied to a large set of anneal experiments, h as identified a mid-gap recombination center that is repeatably genera ted by quenching after the stoichiometric anneal. Lifetime reduction a ssociated with this center is found to correlate both with the degree of compensation and with the amount of indium dopant. Passivation with CdTe is found effective in mitigating the effect.