High breakdown voltage microelectronic device isolation structure with improved reliability

Patent metadata

Field	Value
Publication number	US-9299697-B2
Application number	US-201414277851-A
Country	US
Kind code	B2
Filing date	May 15, 2014
Priority date	May 15, 2014
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A microelectronic device contains a high voltage component having a high voltage node and a low voltage node. The high voltage node is isolated from the low voltage node by a main dielectric between the high voltage node and low voltage elements at a surface of the substrate of the microelectronic device. A lower-bandgap dielectric layer is disposed between the high voltage node and the main dielectric. The lower-bandgap dielectric layer contains at least one sub-layer with a bandgap energy less than a bandgap energy of the main dielectric. The lower-bandgap dielectric layer extends beyond the high voltage node continuously around the high voltage node. The lower-bandgap dielectric layer has an isolation break surrounding the high voltage node at a distance of at least twice the thickness of the lower-bandgap dielectric layer from the high voltage node.

First claim

What is claimed is:

1. A microelectronic device, comprising:
a low voltage node of a high voltage component of the microelectronic device;
a high voltage node of the high voltage component;
a main dielectric at least 2 microns thick disposed between the low voltage node and the high voltage node; and
a lower-bandgap dielectric layer disposed between the main dielectric and the high voltage node, wherein:
the lower-bandgap dielectric layer comprises:
at least a first sub-layer having a bandgap energy less than a bandgap energy of a portion of the main dielectric adjacent to the lower-bandgap dielectric layer; and
a second sub-layer disposed between the first sub-layer and the high voltage node, the second sub-layer having a bandgap energy less than the bandgap energy of the first sub-layer;

the lower-bandgap dielectric layer extends past the high voltage node continuously around the high voltage node, by a distance which is at least twice a thickness of the lower-bandgap dielectric layer;

an isolation break in the lower-bandgap dielectric layer so that the lower-bandgap dielectric layer is not continuous at the isolation break, and the isolation break surrounds the high voltage node.

2. The microelectronic device of claim 1 , wherein the portion of the main dielectric adjacent to the lower-bandgap dielectric layer comprises silicon dioxide-based dielectric material, the first sub-layer comprises silicon oxide nitride, and the second sub-layer comprises silicon nitride.

3. The microelectronic device of claim 1 , wherein the high voltage component is a high voltage capacitor, the low voltage node is a lower plate of the high voltage capacitor, and the high voltage node is an upper plate of the high voltage capacitor.

4. The microelectronic device of claim 3 , wherein the main dielectric comprises a plurality of intra-metal dielectric (IMD) layers comprising silicon dioxide-based dielectric material and inter-level dielectric (ILD) layers comprising silicon dioxide-based dielectric material.

5. The microelectronic device of claim 1 , further comprising a low voltage component disposed outside of the isolation break.

6. The microelectronic device of claim 5 , wherein the low voltage component is a metal oxide semiconductor (MOS) transistor with a gate dielectric layer less than 70 nanometers thick.

7. The microelectronic device of claim 1 , wherein the lower-bandgap dielectric layer comprises a portion disposed outside of the isolation break.

8. The microelectronic device of claim 7 , wherein the portion of the lower-bandgap dielectric layer disposed outside of the isolation break contacts a low voltage element of the microelectronic device.

9. The microelectronic device of claim 1 , wherein an edge of the lower-bandgap dielectric layer at the isolation break is covered with a dielectric material.

Assignees

• Texas Instruments Inc

Inventors

• West Jeffrey Alan
• Bonifield Thomas D
• Williams Byron Lovell

Classifications

• H10D84/813

  Combinations of field-effect devices and capacitor only · CPC title

• H10P14/69433

  the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz · CPC title

• H10P14/69215

  the material being a silicon oxide, e.g. SiO2 · CPC title

• H10P14/6927

  the material being a silicon oxynitride, e.g. SiON or SiON:H · CPC title

• H10W72/536

  the connected ends being ball-shaped · CPC title