Method for preparing memory array with contact enhancement sidewall spacers

A method for preparing a memory array, comprising:

• forming a trench at a front side of a semiconductor substrate, wherein the trench defines laterally separate active areas formed of surface regions of the semiconductor substrate, wherein the active areas are grouped into a first group of the active areas and a second group of the active areas;
• filling an isolation structure in the trench, wherein the isolation structure is filled to a height lower than top surfaces of the active areas;
• recessing the first group of the active areas from the top surfaces of the first group of the active areas, while having the top surfaces of the second group of the active areas covered;
• forming contact enhancement sidewall spacers to laterally surround top portions of the active areas, respectively;
• and
• forming self-assembly monolayers (SAMs) on the top surfaces of the active areas before formation of the contact enhancement sidewall spacers;
• wherein forming the contact enhancement sidewall spacers comprises an epitaxial process;
• wherein the contact enhancement sidewall spacers are semiconductive.