US 4,396,933 A · Dielectrically isolated semiconductor devices

Abstract

A dielectrically isolated semiconductor device can be manufactured. The structure is useable for integrated circuits, including field effect and/or bipolar transistors, wherein a significant savings in surface area and reduction in capacitances can be obtained over prior techniques. The method involves forming a layer of dielectric material upon a semiconductor body, having a diffused region where a bipolar device is to be formed, and then forming an opening in the layer to expose a part of the surface of the diffused region of the semiconductor body. An epitaxial layer of silicon is deposited on top. Single crystal silicon will grow over the exposed silicon area and if a diffused region is present in the substrate a pedestal will outdiffuse through the same area from the buried diffused region. Polycrystalline silicon will grow on top of the dielectric material. The pedestal is formed in a single crystal epitaxial layer of another impurity type. Two other active elements of a bipolar transistor, such as the emitter and intrinsic base regions, are then formed in the same single crystal epitaxial layer while the inactive area, such as the extrinsic base, is formed in polycrystalline silicon. A reach through is made through the dielectric layer to the third element of the transistor, that is collector region.

Claims19

Dependent claims

A semiconductor device comprising a body, said body comprising:

a monocrystalline substrate;
at least a first layer consisting of silicon semiconductor material on a surface of said substrate;
a second layer of insulating material located at only part of the said substrate surface and buried within the body;
and
means forming an isolation zone for isolating part of the first semiconductor layer from another part of the semiconductor layer;
said isolation zone comprising at least partly a third layer of insulating material inset in the first semiconductor layer from its surface and extending down to and at least partly adjoining the second insulating layer;
said third layer consisting of silicon oxide formed by in situ conversion of the semiconductor material of the first semiconductor layer;
the lateral extent of the second layer being different from the lateral extent of the third layer where it adjoins the second layer.

5 more elements

Dependencies are inferred from the claim text.

Dielectrically isolated semiconductor devices

Life of this patent

Dielectrically isolated semiconductor devices

Life of this patent

Abstract

Claims19