Complex testing of semiconductor devices is needed in many different areas from laboratory research to device production screening. Self-heating and a cooling network can be a crucial part of any electronic circuit. That is why special testing measurements are so essential for this science. For such testing the so called semiconductor thermal analyzers are used.
These are complex devices or rather systems of devices that allow performing and controlling numerous series of testing experiments. Semiconductor thermal analyzers' most usual use is testing of diodes, LEDs, MOSFETs, bipolar transistors, functional analog and digital integrated circuits. To perform all the measurements of component thermal parameters semiconductor thermal analyzers use the electrical method of junction temperature measurement. Semiconductor thermal analyzer can also be oriented on measurement of single parameter, like semiconductor thermal resistance testers or semiconductor thermal impedance testers. But no matter how complex the measuring system is, it usually works by the same principle.
Some sort of heat source is used to increase the temperature of tested circuit or semiconductor element and then with a use of sense element all the measurements are made. As a result of test by semiconductor thermal analyzer so called thermal characterization of circuit (or a semiconductor element) can be built. This thermal characterization of a semiconductor circuit (component) is the determination of the temperature response of the semiconductor circuit junctions due to internal self heating. Usually heat generation is concentrated in specific regions of the device and diffuses outward into the package. That means that heat density is the greatest in the heat generating region and becomes progressively less concentrated in other regions of semiconductor element.
To measure different thermal parameter different test schematics are used. For example, to perform electrical junction temperature Measurement Bath method is usually used. In that case the device being tested is placed into stirred dielectric bath and an external heat source is used to change the temperature of this bath. And to measure the temperature of the device thermocouple attached to the case of the circuit is used. In other tests schemes with self-heating of the element can be used. For example, to measure delivery of DC heating power by semiconductor thermal analyzer the device being tested is connected to a power supply with two "Lead Wire Resistances". For better and more precise results a four-wire connection is sometimes used in this scheme.
Modern semiconductor thermal analyzers usually have special software that allows controlling all the parameters easily. Such an option can be very helpful in complex research testings. Working with this software is not that easy but special training is usually included into semiconductor thermal analyzers' price.