# US 2018/0321304 A1 · Apparatus and method for performing avalanche mode delta vsd testing

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- Number: US 2018/0321304 A1
- Document ID: US20180321304A1
- Status: Published application
- Kind: A1
- Application number: 15/587,696
- Filed: 2017-05-05
- Published: 2018-11-08
- Earliest claimed: 2017-05-05
- Assignees: Integrated Technology Corporation
- Applicants: Integrated Technology Corporation
- Inventors: Steven T. Clauter; Ausin Hsu; Gary B. Rogers; Bradley Thomas Wolford
- Web page: https://patentgrep.com/patent/US20180321304A1

## CPC

- G01R 31/2628: {for measuring thermal properties thereof}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

A device and method for performing Avalanche Mode Delta VsD testing of a semiconductor device under test (DUT), include a current source configured to provide energy in the form of a substantially non-decaying current to a DUT for heating of the DUT during an avalanche mode; and test circuitry electrically couplable to the current source and the DUT and configured to perform Avalanche Mode Delta VsD testing of the DUT.

## Claims

### Claim 1

A device for performing Avalanche Mode Delta VsD testing of a semiconductor device under test (DUT), comprising:
a current source configured to provide energy in the form of a substantially non-decaying current to a DUT for heating of the DUT during an avalanche mode; and
test circuitry electrically couplable to the current source and the DUT and configured to perform Avalanche Mode Delta VsD testing of the DUT.

### Claim 2 (depends on 1)

The device of claim 1, wherein the current source has energy storage capacity sufficient to supply an amount of current sufficient to drive the DUT into an avalanche mode and supply current to the DUT in a substantially non-decaying form for heating of the DUT during the avalanche mode.

### Claim 3 (depends on 1)

The device of claim 1, wherein the current source is configured to be quickly turned on and off by opening and closing, respectively, of a switching element which electrically connects the current source and the test circuitry.

### Claim 4 (depends on 1)

The device of claim 1, wherein the test circuitry includes a measurement current source configured to supply current IM for measuring forward voltage drop of a junction of the DUT, and a voltage measurement device for measuring the forward voltage drop of the junction of the DUT.

### Claim 5 (depends on 1)

The device of claim 1, further comprising a control operably connected to the current source and the test circuitry, and configured to control operation of the device during Avalanche Mode Delta VsD testing.

### Claim 6 (depends on 4)

The device of claim 4, wherein the measurement of the forward voltage drop of the junction of the DUT includes an initial, ambient state measurement, termed VsDi, of the forward voltage drop of the junction of the DUT made prior to heating of the DUT, and a final measurement, termed VsDf, made at a final steady state condition reached after the specified amount of energy has been delivered to the DUT during Avalanche Mode.

### Claim 7 (depends on 4)

The device of claim 4, wherein the measurement of the forward voltage drop of the junction of the DUT includes an initial, ambient state measurement, termed VsDi, of the forward voltage drop of the junction of the DUT made prior to heating of the DUT, and a final measurement, termed VsDf, made after the specified time tH for heating has expired during the avalanche mode.

### Claim 8 (depends on 4)

The device of claim 4, wherein the voltage measurement device measures voltage supplied to the DUT during the Avalanche Mode Delta VSD testing, the voltage including drain to source voltage of the DUT and the forward voltage drop of the junction of the DUT.

### Claim 9 (depends on 5)

The device of claim 5, wherein the control causes a gate of the DUT to be biased off when the DUT enters into the avalanche mode, thereby preventing instability and oscillations which occur when a linear mode of operation is used for heating of the DUT.

### Claim 10 (depends on 5)

The device of claim 5, wherein the control causes the avalanche mode to be interrupted by opening a switching element configured to electrically couple the current source and the test circuitry.

### Claim 11 (depends on 10)

The device of claim 10, wherein the control causes the current source to be quickly turned on and off by closing and opening, respectively, of the switching element.

### Claim 12 (depends on 10)

The device of claim 10, wherein the control causes heating period tH of the DUT to be controlled by opening the switching element.

### Claim 13 (depends on 10)

The device of claim 10, wherein the opening of the switching element reduces a measurement time delay tMD which occur after termination of the avalanche mode and up to the point in time where VSD corresponds to the temperature of a die of the DUT.

### Claim 14

A method for performing testing of a power semiconductor device under test (DUT), the method comprising:
driving a DUT using an Avalanche Mode for heating of the DUT, and then performing a Delta VSD testing of the DUT.

### Claim 15 (depends on 14)

The method of claim 14, further comprising:
interrupting the avalanche mode for heating of the DUT by quickly turning on and off a current source for supplying heating current to the DUT during the avalanche mode.

### Claim 16 (depends on 15)

The method of claim 15, further comprising:
providing a fast-cut off of the DUT from the current source;
reducing a measurement time delay required for reaching a steady state for measuring a forward voltage drop of a junction of the DUT after heating of the DUT; and
increasing accuracy of a measurement of the forward voltage drop of the junction of the DUT at a steady state reached after the heating of the DUT by reducing the measurement time delay.

### Claim 17 (depends on 15)

The method of claim 15, wherein interrupting of the avalanche mode is performed by opening a switching element configured to electrically couple the current source and test circuit including the DUT.

### Claim 18 (depends on 17)

The method of claim 17, wherein opening the switching element controls heating current IH supplied from the current source during the avalanche mode during heating period tH.

### Claim 19 (depends on 18)

The method of claim 18, wherein controlling the level of the heating current and the heating period reduces measurement time delay tMD which occurs after a lapse of the heating period and at time at which VSD corresponds to the temperature of the die of the DUT.