Improved film quality of plasma enhanced atomic layer deposition SiO2 using plasma treatment cycle

Chemical, physical, and electrical characteristics of high quality silicon dioxide (SiO2) films grown using low temperature plasma enhanced atomic layer deposition (PE-ALD) have been investigated as a buffer layer for three dimensional vertical nand flash memory devices. The comparative angle resolved x-ray photoelectron spectroscopy studies show the plasma treatment cycle causes to shift the core level binding energy (chemical shifts) in the SiO2 film. The wet etch rates with respect to plasma treatment cycle times were varied due to curing of the SiO2 network defects by Ar+ ions and oxygen radicals. It is assumed that the angle between the bonds linking SiO4 tetrahedra is a critical point understanding the variation in wet etch rate of SiO2. The features of wet etch rate of low temperature high quality SiO2 demonstrated lower than high temperature low-pressure chemical vapor deposition (LP-CVD) SiO2 values. In addition, the better step-coverage compared to that of the LP-CVD SiO2 film was achieved from the deep trench structure having the 20:1 aspect ratio. PE-ALD SiO2 with plasma treatment cycle showed excellent I–V properties with higher breakdown voltage compared to LP-CVD SiO2 and similar to the thermal SiO2 carrier transport plot.