3. GaN heterojunction field-effect transistors

Wide-bandgap materials based on gallium nitride and its alloys possess numerous physical properties that make them today's best candidates for microwave applications where power and robustness are critical.

Gallium nitride and its derivatives offer an unrivalled combination of physical properties:

• a high bandgap (3.4 eV) for GaN, which can exceed 6 eV for AlN,

• a carrier saturation velocity greater than 1x10 ⁷ cm/s,

• a remarkable breakdown electric field (3 MV/cm),

• the possibility of obtaining GaN-based heteroepitaxial layers (AlGaN/GaN, InGaN/GaN, InAlN/GaN) with good transport qualities.

The ability of a material...