power semiconductor
**Power Semiconductors** are **devices designed to switch and convert electrical power at high voltages (100V to 10kV+) and high currents (1A to 1000A+)** — enabling efficient power conversion in electric vehicles, renewable energy inverters, industrial motor drives, and power supplies, where the transition from silicon to wide-bandgap materials (SiC, GaN) is driving a revolution in power electronics efficiency.
**Key Power Device Types**
| Device | Voltage Range | Speed | Application |
|--------|------------|-------|------------|
| Power MOSFET | 20-1000V | Very Fast (MHz) | DC-DC converters, motor drives |
| IGBT | 600-6500V | Medium (kHz) | EV inverters, industrial drives |
| Schottky Diode | 20-1700V | Very Fast | Rectification, PFC |
| Thyristor (SCR) | 1-10 kV | Slow (50/60 Hz) | Grid power, HVDC |
| GaN HEMT | 40-900V | Very Fast (MHz+) | Fast chargers, data center power |
| SiC MOSFET | 600-3300V | Fast (100 kHz+) | EV inverters, solar, grid |
**Silicon Carbide (SiC) — Wide Bandgap**
- Bandgap: 3.26 eV (vs. Si 1.12 eV) → higher breakdown voltage per unit thickness.
- $E_{critical}$ (breakdown field): 10x higher than Si → thinner, lower resistance drift region.
- Advantage: Same 1200V rating at 1/10th the on-resistance → dramatic efficiency improvement.
- Thermal conductivity: 3x higher than Si → better heat dissipation.
**SiC Impact on EVs**
- EV traction inverter upgraded from Si IGBT → SiC MOSFET:
- Efficiency: 96% → 99% = 75% reduction in inverter losses.
- Size: 50% smaller inverter module.
- Range: 5-10% increase in EV driving range from same battery.
- Tesla Model 3 (2018): First mass-market EV with SiC inverter (STMicroelectronics SiC).
**Gallium Nitride (GaN)**
- Bandgap: 3.4 eV. Electron mobility: Very high → fast switching.
- Best for: 40-650V applications at very high switching frequency (>1 MHz).
- **GaN chargers**: USB-C fast chargers (65-240W) — 50% smaller than Si equivalents.
- **GaN-on-Si**: GaN devices grown on standard Si wafers → leverages existing Si fab infrastructure.
- Key players: GaN Systems, Navitas, Infineon, Texas Instruments.
**Power Device Metrics**
| Metric | Definition | Better When |
|--------|-----------|-------------|
| RDS(on) | On-state resistance | Lower |
| BV (Breakdown Voltage) | Max blocking voltage | Higher |
| Switching loss | Energy per switching event | Lower |
| Figure of merit (FOM) | RDS(on) × Qg | Lower |
| Thermal impedance | Junction-to-case thermal path | Lower |
**Market Landscape**
- Power semiconductor market: ~$50B (2024), growing at 7-10% annually.
- SiC market growing at 30%+ CAGR, driven by EV adoption.
- Key vendors: Infineon (#1), ON Semiconductor, STMicroelectronics, Wolfspeed (SiC), Rohm.
Power semiconductors are **the enabling technology for the electrification of everything** — from electric vehicles to solar inverters to data center power supplies, the efficiency of power conversion directly determines energy waste, and the wide-bandgap revolution (SiC/GaN) is delivering step-function improvements that make new applications economically viable.