Defect Losses under Different Processes, Stress, Recovery, and Anneal Conditions

Abstract

It is well known that degradation limits device lifetime. Early works were focused on defect generation and it is generally believed that, once a defect is created, it will be there forever. Although some defects can be neutralized after stress, they will recharge when the stress is resumed. Recently, we show that the generated defects themselves are not stable and can be lost. In this work, we investigate defect losses on samples fabricated under different conditions and the loss after different stress, recovery, and anneal conditions. It is found that the defect losses are a generic phenomenon and occur in both plasma SiON and ALCVD SiON/HfSiON stack. It will be shown that the defect losses are insensitive to the level of neutralization during the anneal. The losses have been observed at a temperature as low as 125 oC.