Method of forming an active area with floating gate negative offset profile in FG NAND memory

摘要

A stack can be patterned by a first etch process to form an opening defining sidewall surfaces of a patterned material stack. A masking layer can be non-conformally deposited on sidewalls of an upper portion of the patterned material stack, while not being deposited on sidewalls of a lower portion of the patterned material stack. The sidewalls of a lower portion of the opening can be laterally recessed employing a second etch process, which can include an isotropic etch component. The sidewalls of the upper portion of the opening can protrude inward toward the opening to form an overhang over the sidewalls of the lower portion of the opening. The overhang can be employed to form useful structures such as an negative offset profile in a floating gate device or vertically aligned control gate electrodes for vertical memory devices.

主权项

1. A semiconductor device comprising:
a stack of layers arranged in the following order in a first direction extending transverse to a major surface of a substrate: a semiconductor channel; a tunnel dielectric layer; and a charge storage region electrically separated from the semiconductor channel by the tunnel dielectric layer; andwherein:
the semiconductor channel has a first sidewall; the charge storage region has a first sidewall; and the first sidewall of the semiconductor channel is overhung by the first sidewall of the charge storage region by a first offset distance in a second direction transverse to the first direction; and the first offset distance is greater than 1 nm.