Semiconductor device having an optical device degradation sensor

Patent metadata

Field	Value
Publication number	US-11940489-B2
Application number	US-202117502335-A
Country	US
Kind code	B2
Filing date	Oct 15, 2021
Priority date	Oct 15, 2021
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

A semiconductor device includes: a semiconductor body; an electrical device formed in an active region of the semiconductor body, the active region including an interface between the semiconductor body and an insulating material; and a sensor having a bandwidth tuned to at least part of an energy spectrum of light emitted by carrier recombination at the interface when the electrical device is driven between accumulation and inversion, wherein an intensity of the emitted light is proportional to a density of charge trapping states at the interface, wherein the sensor is configured to output a signal that is proportional to the intensity of the sensed light. Corresponding methods of monitoring and characterizing the semiconductor device and a test apparatus are also described.

First claim

What is claimed is:

1. A semiconductor device, comprising:
a semiconductor body;
an electrical device formed in an active region of the semiconductor body, the active region including an interface between the semiconductor body and an insulating material; and
a sensor having a bandwidth tuned to at least part of an energy spectrum of light emitted by carrier recombination at the interface when the electrical device is driven between accumulation and inversion, wherein an intensity of the emitted light is proportional to a density of charge trapping states at the interface, wherein the sensor is configured to output a signal that is proportional to the intensity of the emitted light,
wherein the sensor is monolithically integrated in the same semiconductor body as the electrical device, and
wherein the sensor is formed in the active region of the semiconductor body.

2. The semiconductor device of claim 1 , wherein the semiconductor body is a SiC semiconductor body, wherein the electrical device is a transistor, wherein the insulating material is a gate dielectric, wherein the interface is a channel interface, and wherein a change in magnitude of the signal output by the sensor is proportional to a threshold voltage drift.

3. The semiconductor device of claim 1 , further comprising:
an amplification circuit configured to amplify the signal output by the sensor.

4. The semiconductor device of claim 3 , further comprising:
a condition monitoring circuit configured to compare an output of the amplification circuit to a threshold.

5. The semiconductor device of claim 4 , wherein the condition monitoring circuit is further configured to disable the electrical device or adjust a gate voltage for the electrical device to maintain a gate overdrive at a constant value, if the output of the amplification circuit crosses the threshold.

6. The semiconductor device of claim 3 , wherein the sensor is monolithically integrated in the same semiconductor body as the electrical device in a first semiconductor die, wherein the amplification circuit is disposed in a second semiconductor die, wherein the first semiconductor die further comprises a pin electrically coupled to the sensor, wherein the pin of the first semiconductor die is electrically coupled to a corresponding pin of the second semiconductor die, and wherein the pin of the second semiconductor die is electrically coupled to an input of the amplification circuit.

7. The semiconductor device of claim 1 , wherein a direct optical path in the semiconductor body optically couples the sensor to the interface for at least part of the energy spectrum of the light emitted by carrier recombination at the interface when the electrical device is driven between accumulation and inversion.

8. The semiconductor device of claim 1 , wherein the sensor is disposed under a gate pad for the electrical device or adjacent a gate runner extending from the gate pad.

9. The semiconductor device of claim 1 , wherein the sensor is disposed in a trench formed in the semiconductor body.

10. The semiconductor device of claim 9 , wherein the sensor comprises a semiconductor material of a first conductivity type disposed in a lower part of the trench and a semiconductor material of a second conductivity type opposite the first conductivity type disposed on the semiconductor material of the first conductivity type in an upper part of the trench.

11. The semiconductor device of claim 9 , wherein the sensor comprises a first layer of semiconductor material of a first conductivity type lining sidewalls and a bottom of the trench and a second layer of semiconductor material of a second conductivity type opposite the first conductivity type formed over the first layer.

12. The semiconductor device of claim 1 , wherein the bandwidth of the sensor is tailored to a subrange of the energy spectrum of the light emitted by carrier recombination at the interface when the electrical device is driven between accumulation and inversion, the subrange of the energy spectrum being most closely correlated to the density of charge trapping states at the interface.

13. A semiconductor device, comprising:
a semiconductor body;
an electrical device formed in an active region of the semiconductor body, the active region including an interface between the semiconductor body and an insulating material;
a sensor having a bandwidth tuned to at least part of an energy spectrum of light emitted by carrier recombination at the interface when the electrical device is driven between accumulation and inversion, wherein an intensity of the emitted light is proportional to a density of charge trapping states at the interface, wherein the sensor is configured to output a signal that is proportional to the intensity of the emitted light; and
an amplification circuit configured to amplify the signal output by the sensor,
wherein the sensor is monolithically integrated in the same semiconductor body as the electrical device in a first semiconductor die,
wherein the amplification circuit is disposed in a second semiconductor die,
wherein the first semiconductor die further comprises a pin electrically coupled to the sensor,
wherein the pin of the first semiconductor die is electrically coupled to a corresponding pin of the second semiconductor die, and
wherein the pin of the second semiconductor die is electrically coupled to an input of the amplification circuit.

14. A semiconductor device, comprising:
a semiconductor body;
an electrical device formed in an active region of the semiconductor body, the active region including an interface between the semiconductor body and an insulating material; and
a sensor having a bandwidth tuned to at least part of an energy spectrum of light emitted by carrier recombination at the interface when the electrical device is driven between accumulation and inversion, wherein an intensity of the emitted light is proportional to a density of charge trapping states at the interface, wherein the sensor is configured to output a signal that is proportional to the intensity of the emitted light,
wherein the sensor is monolithically integrated in the same semiconductor body as the electrical device, and
wherein the sensor is formed in an edge termination region of the semiconductor body that laterally surrounds the active region and that is devoid of any fully functional cells of the electrical device.

15. A semiconductor device, comprising:
a semiconductor body;
an electrical device formed in an active region of the semiconductor body, the active region including an interface between the semiconductor body and an insulating material; and
a sensor having a bandwidth tuned to at least part of an energy spectrum of light emitted by carrier recombination at the interface when the electrical device is driven between accumulation and inversion, wherein an intensity of the emitted light is proportional to a density of charge trapping states at the interface, wherein the sensor is configured to output a signal that is proportional to the intensity of the emitted light,
wherein the sensor is monolithically integrated in the same semiconductor body as the electrical device, and
wherein the sensor is disposed under a gate pad for the electrical device or adjacent a gate runner extending from the gate pad.

16. A semiconductor device, comprising:
a semiconductor body;
an electrical device formed in an active region of the semiconductor body, the active region including an interface between the semiconductor body and an insulating material; and
a sensor having a bandwidth tuned to at

Assignees

• Infineon Technologies Ag

Inventors

• Aichinger Thomas
• Feil Maximilian Wolfgang
• Kabakow Andre
• Reisinger Hans

Classifications

• H10W90/00

  Package configurations · CPC title

• H10F39/103

  the at least one element covered by H10F30/00 having potential barriers, e.g. integrated devices comprising photodiodes or phototransistors · CPC title

• G01R31/311 Primary

  of integrated circuits {(G01R31/31728 takes precedence)} · CPC title

• G01R31/00

  Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere ({measuring superconductive properties G01R33/1238;} testing line transmission systems H04B3/46; testing or measuring semiconductors or solid state devices during manufacture {H10P74/00}) · CPC title

• H01L25/167

  Electricity · mapped topic