How many manufacturing processes are there for MOSFET products?
There are several manufacturing processes for MOSFET products, such as trench, deep trench, planar, multi-layer epitaxy, and superjunction. What are the differences between them, what are the differences in their applications and advantages and disadvantages, and who are the representative manufacturers?
Planar Process
The earliest power MOSFET structure: the gate spans the drift region formed by multi-layer epitaxy to create the conduction channel. The process is mature, wafer cost is low, and avalanche energy capability and short-circuit robustness are good — but cell density is low and on-resistance is relatively high. Today it survives mainly in high-voltage applications (above 500 V) and in scenarios with strict ruggedness requirements, such as lighting drivers and industrial auxiliary power supplies.
Trench Process
The gate is etched into trenches on the silicon surface so the channel runs vertically. Cell density rises substantially and on-resistance falls well below planar devices, making trench the absolute mainstream for low- and medium-voltage parts (30–200 V): phone fast chargers, battery protection, power tools and automotive low-voltage electronics are almost exclusively trench devices. The price is a higher bar for gate-oxide reliability design and faster switching dv/dt, which demands better gate drive and layout practice.
Deep Trench and Shielded Gate
Building on the trench structure, the trench is made deeper and a shield or split electrode is introduced. This pushes gate charge (Qg) and Miller charge even lower, combining low on-resistance with low switching loss — the preferred structure for high-frequency DC-DC converters such as 48 V server power supplies and telecom power supplies.
Super Junction Process
A paradigm shift for high-voltage MOSFETs: alternating P/N pillars are implanted in the drift region, breaking the square-law trade-off between breakdown voltage and on-resistance. In the 600–900 V range, on-resistance is far lower than that of a planar device with the same rating. Switching power supplies, PV inverters and the PFC stage of charging piles are its home turf. The cost is a longer process sequence and a body diode with only average reverse-recovery behaviour, so hard-switched high-current designs need careful evaluation.
Multi-Layer Epitaxy
Epitaxial layers with different doping concentrations are grown one on top of another on a heavily doped substrate, giving fine control over the balance between breakdown voltage and on-resistance. It is common in high-voltage devices and customised requirements, and is also one of the process levers for improving wafer utilisation and lowering cost.
Representative Manufacturers
- High-voltage planar/trench: Infineon, onsemi, STMicroelectronics, ROHM;
- Super junction: Infineon, onsemi, Toshiba; in China, CR Micro and Oriental Semiconductor are already in volume production;
- Low- and medium-voltage trench: Nexperia, Vishay; in China, Silan, NCE Power and CR Micro have broad coverage;
- Automotive-grade trench: led by Infineon, onsemi and ST, with Chinese vendors ramping up qualification.
How to Choose
No process is universally better: for low and medium voltage, look at cell density (the trench family); for high voltage at high frequency, look at superjunction; for high voltage with high ruggedness, look at planar. On the procurement side, add package, automotive qualification and supply stability to the assessment. If you are unsure, hand us three parameters — topology, switching frequency and bus voltage — and our selection support will recommend the most suitable process route for your actual operating conditions.