US 5,314,836 AGranted

Method of making a single electrode level CCD

AssigneeEastman Kodak Company

InventorJames P. Lavine

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Abstract

The disclosure is directed to a method of forming a CCD with two sets of gate electrodes in a single layer of a conductive material. The method comprises forming a channel region in a body of a semiconductor material along a surface thereof and forming a layer of conductive material over and insulated from the surface of the body. A first masking layer is formed on the conductive layer and spaced strips of polycrystalline silicon are formed on the first masking layer. Using a portion of the spaces between the strips as a mask, impurities of a conductivity type opposite that of the channel region are embedded in the channel region to form spaced barrier regions along the channel region. A layer of silicon dioxide is formed over each of the strips and the spaces between the strips are filled with polycrystalline silicon. The portion of the silicon dioxide layer at one end of each of the strips is etched away to expose a portion of the first masking layer. The exposed portions of the first masking layer are etched away to form grooves through the first masking layer to the conductive layer. The portions of the conductive layer at the bottom of the grooves are then etched away to define the conductive layer into closely spaced gate electrodes.

Claims19

Dependent claims

A method of making a CCD comprising the steps of:

forming a layer of a conductive material over and insulated from a surface of a body of a semiconductor material of one conductivity type;
forming a first masking layer over the conductive layer;
forming spaced strips of a material which can be oxidized and which can be etched by an etchant which does not effectively etch the material of the first masking layer on the surface of the first masking layer;
forming a layer of an oxide over each of the strips with the oxide layer extending across the end edges of the strips so as to extend partially across the spaces between the strips;
forming a layer of a non-single crystalline silicon on the surface of the first masking layer in the remaining portions of the spaces between the strips with the surface of the non-single crystalline silicon layer being substantially planar with the surface of the oxide layer over each of the strips;
forming a second masking layer over each of the strips which extends over the portion of the oxide layer at one end of the strips leaving exposed the portion of the oxide layer at the other end of the strips;
etching away the exposed portions of the oxide layers at the other end of each strip to expose a portion of the first masking layer thereunder;
etching through the exposed portions of the first masking layer to the conductive material layer to form spaced grooves in the first masking layer which expose portions of the surface of the conductive layer;
and then
using the spaced grooves as a guide, dividing the conductive material layer into spaced gate electrodes.

7 more elements

A method of making a CCD in a body of a semiconductor material of one conductivity type comprising the steps of:

forming in the body a channel region of a conductivity type opposite that of the body, the channel region extending to and along a surface of the body;
forming on the surface of the body and over the channel region a layer of an insulating material;
forming a layer of a conductive material on the insulating material layer;
forming a first masking layer on the conductive layer;
forming spaced strips of polycrystalline silicon on the first masking layer;
forming in the channel region a barrier region of the one conductivity type beneath a portion of each of the spaces between the strips of the polycrystalline silicon;
forming a layer of silicon dioxide on each of the strips, each of the silicon dioxide layers extending across the end edges of the strips so as to extend partially across the spaces between the strips;
forming a layer of polycrystalline silicon on the surface of the first masking layer in the remaining portions of the spaces between the strips with the surface of the polycrystalline silicon layer being substantially planar with the surface of the silicon dioxide layers on the strips;
forming a third masking layer over each of the strips which extends over a portion of the portion of the silicon dioxide layer only at one end of the strips leaving exposed the portion of the silicon dioxide layer at the other end of each strip;
etching away the exposed portion of the silicon dioxide layer at the other end of each of the strips to expose a portion of the first masking layer thereunder;
etching through the exposed portions of the first masking layer to the conductive material layer to form spaced grooves in the first masking layer which expose portions of the conductive material layer;
and then
etching through the exposed portions of the conductive material layer to define the conductive layer into spaced gate electrodes.

10 more elements

Dependencies are inferred from the claim text.