Gallium Nitride (GaN) belongs to the family of wide bandgap (WBG) materials. It is a binary compound whose molecule is formed from one atom of Gallium (III-group, Z=31) and one of Nitrogen (V-group, Z=7) with a wurztite hexagonal structure.



ST’s  GaN HEMTs (High Electron Mobility Transistors) represent a major step forward in power electronics providing high-frequency operation, with increased efficiency and higher power density compared to silicon based transistors.

AlGaN/GaN High Electron Mobility Transistor (HEMT)


  • Low Ron due to high two-dimensional electron gas (2DEG) density with ns ~ 9x1012 cm-2
  • High breakdown voltage linked to high bandgap (3.4eV)
  •  Low capacitance: no junction to deplete


  • Better on-resistance than Si with higher operation frequency (due to high mobility)
  • Bi-directionality (advantageous in some circuit topologies)
  • Lateral device (suitable for integration of power with control circuitry)

GaN devices allow gate charge reduction without sacrificing on-resistance, leading to power savings and total system downsizing

ST and GaN

ST started working on wide bandgap materials in 1996 with SiC MOSFETs and diodes and has become one of the main players in the market. We are now expanding our portfolio of wide bandgap power devices with the GaN devices.

We have developed the first 650V normally-off GaN High-electron-mobility transistor (HEMT). The first samples of 650V GaN HEMTs are expected in Q3 ’19 and 100V prototypes by year-end.

ST GaN products will address a wide variety of applications such as adaptors (PC, portable electronics, wall USB chargers, wireless chargers), power factor correction (PFC) servers and DC/DC converters in segments as diverse as space and avionics, telecom and industrial.

Future developments of GaN products will target the automotive environment including on-board chargers for EV and mild-hybrid powertrains.



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