DUAL GATE STRUCTURE

摘要

Methods for forming a dual gate structure for a vertical TFT are described. The dual gate structure may be formed by performing a first etching process that includes forming a first set of trenches by etching a first set of oxide pillars to a first depth and forming a second set of trenches by etching a second set of oxide pillars to a second depth higher than the first depth, forming a first set of gate structures within the first set of trenches, forming a second set of gate structures within the second set of trenches, performing a second etching process that includes forming a third set of trenches by etching the first set of gate structures from a second initial depth to a third depth and forming a fourth set of trenches by etching the second set of gate structures to a fourth depth higher than the third depth.

主权项

1. A method for forming a dual gate structure for a vertical TFT, comprising:
performing a first etching process, the first etching process includes etching a first set of oxide pillars of a plurality of oxide pillars to a first initial depth, the plurality of oxide pillars includes a second set of oxide pillars different from the first set of oxide pillars; performing a second etching process subsequent to the performing the first etching process, the second etching process forms a first set of trenches by etching the first set of oxide pillars from the first initial depth to a first depth, the second etching process forms a second set of trenches by etching the second set of oxide pillars to a second depth higher than the first depth; forming a plurality of gate dielectrics within the first set of trenches and the second set of trenches; and forming a first set of gate structures and a second set of gate structures, the forming the first set of gate structures and the second set of gate structures includes filling the first set of trenches and the second set of trenches with a gate material subsequent to the forming the plurality of gate dielectrics.