Which of the following materials supports the highest frequency of operation when used in MMICs?

Monolithic Microwave Integrated Circuits (MMICs) require semiconductor materials that can handle extremely high radio frequencies. Gallium nitride (GaN) is a wide-bandgap semiconductor that provides exceptional electron mobility and thermal conductivity compared to standard materials. Because of these physical properties, GaN can support significantly higher frequencies and greater power outputs than traditional silicon. Silicon nitride and silicon dioxide are typically used as insulators or dielectric layers in manufacturing, not as the active high-frequency semiconductor material itself.