National Semiconductor Corporation

Jonggook Kim

Prasad Chaparala

Yun Liu

Joseph A De Santis

Barry O'Connell

A current mirror method is provided that can be utilized to evaluate thermal issues is silicon-on-insulator (SOI) bipolar junction transistors (BJTs). The method significantly improves safe operating area (SOA) measurement sensitivity. Unlike conventional methods, the current mirror method can provide quantitative analysis of the BJTs thermal instability over a wide power range, even in the apparent SOA of the device. This method can also predict and evaluate SOA with respect to emitter ballast resistance and current crowding.

Current mirror methodology quantifying time dependent thermal instability accurately in SOI BJT circuitry

A test methodology is provided for testing metal-insulator-metal (MIM) capacitor structures under high temperatures at the wafer level. A resistor is formed on a region of dielectric isolation material formed in a semiconductor substrate. The MIM capacitor is formed over the resistor and separated therefrom by dielectric material. A metal thermometer, formed from the same material as the plates of the MIM capacitor, is placed above the resistor and in close proximity to the capacitor. High current is forced through the resistor, causing both the metal thermometer and the MIM capacitor to heat up along with the resistor. The change in resistance of the metal thermometer is monitored. Using the known temperature coefficient of resistance (TCR) for the metal used to form both the capacitor and the thermometer, changes in the measured resistance of the metal thermometer are converted to temperature.

Method for testing metal-insulator-metal capacitor structures under high temperature at wafer level

A test structure and a test methodology are provided for testing metal-insulator-metal (MIM) capacitor structures under high temperatures at the wafer level. The test structure includes a resistor formed on a region of dielectric isolation material formed in a semiconductor substrate. The MIM capacitor is formed over the resistor and separated therefrom by dielectric material. A metal thermometer, formed from the same material as the plates of the MIM capacitor, is placed above the resistor and in close proximity to the capacitor. High current is forced through the resistor, causing both the metal thermometer and the MIM capacitor to heat up along with the resistor. The change in resistance of the metal thermometer is monitored. Using the known temperature coeffecient of resistance (TCR) for the metal used to form both the capacitor and the thermometer, changes in the measured resistance of the metal thermometer are converted to temperature.

Method and structure for testing metal-insulator-metal capacitor structures under high temperature at wafer level

A method for quantifying safe operating regions within a safe operating area (SOA) for a bipolar junction transistor (BJT) by driving the device under test (DUT) as part of a current mirror circuit and monitoring variances in the current mirror ratio for various biasing conditions.

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San Jose, CA, United States of America

Jonggook Kim