Analysis and Reliability Test to Improve the Data Retention Performance of EPROM Circuits

Jiyuan Luan and Michael DiVita
Texas Instruments


Data retention lifetime is an important specification for the long term durability of an EPROM circuit. While most of the published EPROM data retention results are based on empirical data, this paper presents an analytical approach which can be used to quantify EPROM data retention lifetime based on its circuit implementation. Two types of EPROM circuits are analyzed with this approach – a single transistor EPROM circuit which is commonly used for high memory density applications as well as a differential EPROM circuit which is commonly used for analog parameter trim. In both cases, the minimal residual charge requirement on the floating gate of the EPROM device is derived from the EPROM data retention test criteria, which can be used to directly compare the data retention performance among different EPROM circuits. The results of the analysis reveal the great impact of circuit implementation on determining EPROM data retention lifetime, and provide valuable insights on improving the reliability of EPROM circuits. The result of this analysis is further validated by wafer level reliability test (WLR) done on an actual IC implementation, which suggests a good agreement between theoretical analysis and actual WLR data.