An effective process to remove etch damage prior to selective epitaxial growth in 3D NAND flash memory

An effective post etch treatment (PET) process was proposed to eliminate etch damage in the channel hole, of which the depth and the aspect ratio is beyond 3 m and 30:1 respectively, prior to selective epitaxial growth (SEG) in three dimensions (3D) NAND flash memory. In this work, it is demonstrated that the damaged layer both at the channel hole bottom and sidewall induced by capacitively coupled plasma (CCP) was effectively eliminated using low energy plasma of CL2 + NF3/CH2F2 in PET, and then obtaining an excellent surface condition in channel hole and fabricating a void-free SEG epitaxial layer.