Electron beam fabricated IGFETs

One of the concerns with electron beam pattern definition of IGFETs is the effect of radiation on transfer characteristics. Several types of devices with different gate structures have been fabricated using electron beam lithography. A description of the structures is presented with emphasis on horizontal geometries. The critical device parameters are then discussed and compared with those of IGFETs fabricated with conventional photolithography, and also with conventional devices subjected to electron radiation. Device characteristics are shown after several annealing conditions. It is found that radiation effects can be removed totally on MOS structures; however, residual effects are observed on MNOS and SNOS devices having vertical structures as described. A model for radiation effects and annealing behavior is presented.