INVESTIGATION OF RADIATION EFFECTS IN SEMICONDUCTORS.

Abstract : This program consists of two tasks and involves the investigation of fast neutron radiation effects in semiconductor devices. The object of Task I is (a) to determine bulk, epitaxial, and diffused-layer neutron-damage constants in silicon and (b) to correlate them with device parameters. The objectives of Task II are the correlations of neutron degradation of h sub FE with physical device constants and damage mechanisms. To accomplish these objectives, the following work is being performed. (1) A model is being developed and verified which predicts the variations of h sub FE with neutron fluence and current density in terms of the physical device constants. (2) A test pattern is being fabricated with various transistor base widths and concentration gradients. This test bar will be exposed to several levels of neutron fluence in order to develop and verify a model for h sub FE degradation. Photomasks and materials for the Task I and II studies have been received. Profiles have been chosen and diffusions are underway. The initial irradiation date has tentatively been set for 23 September. The computer program for the prediction of the h sub FE versus neutron fluence has been modified. Both the input and the recombination models have been revised. (Author)