A new method to quantify retention-failed cells of an EEPROM CAST

The cell array stress test (CAST) is a very simple tool to study one of the main issues of Non Volatile Memory reliability: data retention. However, it is not possible to easily quantify and localise the retention-failed cells of a CAST. Thus, a new experimental technique to localize and to quantify retention-failed EEPROM cells into a CAST is presented in this paper. This new technique is based on light emission microscopy; the aim is to observe light emission coming from cells and to localize their position with accuracy on CAST area. It is a visual and non destructive method which validity has been shown on cycled cells after a retention test.