From GaAs to SiC: Measuring Resistivity in Compound Semiconductors


In an era characterized by a surging demand for advanced power devices, ultra-high frequency radio equipment, and other cutting-edge products, the significance of compound semiconductors has never been more pronounced. The world's growing energy needs, particularly in sectors like electric or hybrid cars and renewable energy management, emphasize the importance of using electricity with minimal loss—making these materials indispensable for achieving a greener, more sustainable future. But how do we ensure the reliability and efficiency of these semiconductors? The answer: by meticulously measuring their resistivity.

Compound semiconductors are a diverse class of materials, synthesized from two or more elements sourced from different groups in the periodic table. Gallium arsenide (GaAs), silicon carbide (SiC), and gallium nitride (GaN) stand as quintessential examples, each boasting distinct properties that render them invaluable across a wide range of applications. These remarkable compounds have become pivotal in addressing our increasing energy needs, driving innovation in fields as varied as high-frequency electronics, optoelectronics, and power electronics.

Gallium Arsenide (GaAs)

Gallium arsenide (GaAs) is renowned for its superior electron mobility and saturated electron velocity compared to silicon. This makes GaAs an ideal candidate for high-speed electronic devices. For instance, it's extensively utilized in microwave amplifiers and high-frequency transistors. Moreover, its prowess in optoelectronics is evident with its application in light-emitting diodes (LEDs) and laser diodes. In the realm of compound semiconductor substrate resistivity, GaAs finds its niche in RF and optoelectronics/photonics.

Silicon Carbide (SiC)

Silicon carbide (SiC) is characterized by its wide bandgap. This allows SiC to function efficiently at elevated temperatures and voltages, outperforming silicon in these aspects. SiC's applications are vast, spanning from high-power electronic devices, including power electronics and high-voltage devices, to radio frequency devices. Additionally, SiC's optoelectronic capabilities are showcased in devices like blue LEDs and UV photodetectors. When it comes to compound semiconductor substrate resistivity, SiC is predominantly used in RF and high-power electronics.

Both GaAs and SiC offer a competitive edge over silicon in specific applications, courtesy of their unique properties. However, it's important to note that key properties, such as electrical resistivity and electrical conductivity, can vary depending on their manufacturing conditions. Hence, robust compound material characterization is essential.

Methods to Measure Resistivity in Compound Semiconductors

  • Contactless Capacitance Technique: COREMA systems by Semilab employ this technique for an accurate resistivity characterization of semi-insulating compound semiconductors. The method involves a capacitive measurement circuit gauging the impedance via an oscillating circuit, ensuring charge balance and system stabilization.
  • Non-Contact Sheet Resistance by Eddy Current: Rooted in the principle that an alternating current in a coil induces an alternating eddy current in a conducting material, this method offers precision and efficiency.
  • The Four Point Probe (4PP): 4PP is a widely used contact technique for monitoring doping density, resistivity, or emitter sheet resistance values. The separation of voltage and current electrodes eliminates the effect of contact resistance from the measurement result.
  • Microwave based  Mobility Measurement System for RF GaN Market: A state-of-the-art system, it characterizes charge carrier density, charge carrier mobility and sheet resistance of compound semiconductors without contact or destruction.

Uniformity in resistivity and mobility values is paramount for optimal process execution. The above methods, non-contact and non-destructive, often unveil properties intrinsically linked to device characteristics or performance.

At Semilab, we understand the intricacies of resistivity measurement and its paramount importance in compound semiconductors. Our range of products, especially those tailored for resistivity measurement in semi-insulators, are designed with precision, efficiency, and the needs of experienced professionals in mind. Delve deeper into the best in resistivity measurement solutions. Or, contact us today for more information.  Your journey towards mastering the art of resistivity in compound semiconductors begins with us.


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