HARD ERROR DOSE DISTRIBUTIONS OF GATE OXIDE ARRAYS IN THE LABORATORY AND SPACE ENVIRONMENTS

Hard errors or ''stuck bits'' observed in a single memory can occur ov er a broad range of macroscopically measured doses. It is shown here t hat a major contributing factor to this is the microscopic variation o f deposited dose across the large array of gate oxides composing the m emory. In addition, processing variations also contribute to the sprea ding of hard error doses. A statistical model of these factors is pres ented and compared to Co-60 data. Comparisons are then made between th e hard error dose distribution for Co-60 and that expected in the hear t of the proton belts. It is shown that even though the average hard e rror dose in the proton belts is greater, the onset hard error dose ca n be less. Thus, the relations between the onset dose for hard errors in the two environments should be thoroughly understood before qualify ing parts for space applications.