US 5,629,235 A · Method for forming damage-free buried contact

Abstract

The present invention is related to a method for forming a damage-free buried contact. The method according to the present invention includes steps of a) providing a silicon substrate; b) forming an oxide layer on the silicon substrate; c) forming a first conductive layer on the oxide layer; d) defining a buried contact region on the first conductive layer on the first conductive layer; e) removing a portion of the first conductive layer according to a shape of the buried contact region; f) implanting ions in the buried contact region to form an ion-implantation region under the oxide layer; and f) removing a portion of the oxide layer to obtain the buried contact. The step f) can be executed either before or after the step f). The present invention provides a method for forming a buried contact by which trench will not be occurred on the silicon substrate during the etching process thereof, so that a damage-free buried contact can be obtained.

Claims38

Dependent claims

A method for forming a damage-free buried contact, comprising the steps of:

a) providing a silicon substrate;
b) forming an oxide layer on said silicon substrate;
c) forming a first conductive layer on said oxide layer;
d) defining a buried contact region on said first conductive layer;
e) removing a portion of said first conductive layer according to a shape of said buried contact region;
f) implanting ions in said buried contact region to form an ion implantation region under said oxide layer;
g) removing a portion of said oxide layer to obtain said buried contact;
h) forming a second conductive layer on said buried contact and said first conductive layer;
i) forming a polysilicon layer on said second conductive layer;
j) defining a drain/source reserve region;
and
k) removing portions of said polysilicon layer and said first and second conductive layers selectively against said silicon substrate according to a shape of said drain/source reserve region to form a source/drain region.

9 more elements

Dependencies are inferred from the claim text.

Method for forming damage-free buried contact

Life of this patent

Method for forming damage-free buried contact

Life of this patent

Abstract

Claims38