Optimization of HfO2 Growth Process by Atomic Layer Deposition (ALD) for High Performance Charge Trapping Flash Memory Application

摘要

ALD process of HfO_2 trapping layer with TEMAH and H_2O as precursors is systematically investigated. By adjusting ALD process parameters of deposition temperature, purge gas cycle mode, and purge time, HfO_2 film quality is effectively improved for charge trapping memories (CTM) application. It is found that a large memory window of 4.4V can be obtained for devices with parameters of 150°C deposition temperature, one TEMAH-one water cycle mode and 5s purge time. Enhancement of memory performance is attributed to the part transformation of chemisorption into physisorption when depositing the trapping layer. For further confirmation of the conclusion, both MHOS and MAHOS structures are employed. The findings provide a guide for future design of CTM.