RETENTION TESTING OF MNOS LSI MEMORIES

User-oriented test methods for MNOS LSI memories with built-in test modes have been developed. Their application is demonstrated on the commercial ER3401 memory. The memory retention is evaluated in two cases-the static retention time in power-down or in stand-by and the read retention during repeated reading, i.e., the maximum number of read cycles. In the first case, the two loss mechanisms, tunneling and thermal excitation of stored charge, are evaluated. separately. and their - influence is combined. In the second case, the limiting mechanism is slow writing by the read signal. On bases of these investigations, astatic retention time of 60 yr at 70° C and 2 yr at 125° C is predicted and a read retention of 3. 1011 read cycles at 70°C and 2·109cycles at.125°C is found for the ER3401; Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.