US 8,525,290 B2 · Method of forming memory cell access device

Abstract

A memory device includes an access device including a first doped semiconductor region having a first conductivity type, and a second doped semiconductor region having a second conductivity type opposite the first conductivity type. Both the first and the second doped semiconductor regions are formed in a single-crystalline semiconductor body, and define a p-n junction between them. The first and second doped semiconductor regions are implemented in isolated parallel ridges formed in the single-crystal semiconductor body. Each ridge is crenellated, and the crenellations define semiconductor islands; the first doped semiconductor region occupies a lower portion of the islands and an upper part of the ridge, and the second doped semiconductor region occupies an upper portion of the islands, so that the p-n junctions are defined within the islands.

Claims25

Dependent claims

A method for forming a memory cell access array, comprising:

providing a single-crystalline semiconductor body having a first conductivity type;
forming a layer of a hard mask material over the semiconductor body;
forming first trenches in a first direction to a first depth in the semiconductor body, resulting in ridges surmounted by a patterned hard mask;
depositing an antireflective coating material to fill the first trenches and to form a thin layer of antireflective coating material over the patterned hard mask;
forming second isolation trenches in a direction orthogonal to the first direction to a second depth less than the first depth, resulting in crenellations in the ridges isolating single-crystalline semiconductor islands surmounted by hard mask material;
filling the first and second trenches with a dielectric fill and planarizing to expose the hard mask material;
removing the hard mask material;
performing a first implant of a second conductivity type to a depth less than the first depth;
and
performing a second implant of the first conductivity type to a depth less than the depth of the first implant.

7 more elements

Dependencies are inferred from the claim text.

Method of forming memory cell access device

Life of this patent

Method of forming memory cell access device

Life of this patent

Abstract

Claims25