Diamond Power Devices Reach New High-Voltage and High-Temperature Milestones

Diamond Power Devices Reach New High-Voltage and High-Temperature Milestones

A Diasemi client's fourth-generation semiconductor research team has reported progress in two diamond-based power devices: a diamond Schottky barrier diode (SBD) and a hydrogen-terminated diamond MOSFET. The reported results include high breakdown voltages, elevated-temperature operation and an Au-free ohmic-contact process, highlighting the potential of diamond for extreme-environment power electronics.

The reported diamond SBD achieved a breakdown voltage above 3,000 V without a field-plate structure, with a Baliga figure of merit (BFOM) above 25 MW/cm². The device was also reported to operate at 500°C.

Diamond's ultra-wide bandgap, high critical electric field and high thermal conductivity make it attractive for high-voltage and high-temperature applications. However, practical implementation remains challenging because of difficulties in n-type doping and epitaxial growth, metal/diamond interface control, edge termination, passivation and high-temperature contact reliability.

The second device, a hydrogen-terminated diamond MOSFET, uses a two-dimensional hole gas formed near the hydrogen-terminated diamond surface as its conduction channel. The reported device achieved a breakdown voltage above 2,500 V and a BFOM of 31 MW/cm², while maintaining stable performance at 400°C.

The research team also reported an Au-free ohmic-contact process. Eliminating gold could help address contamination concerns associated with conventional semiconductor manufacturing and potentially improve compatibility with established fabrication processes.

Despite these advances, diamond power electronics remains at an early development stage. Key challenges include large-area single-crystal diamond growth, precise doping, low-resistance contacts, surface and interface stability, passivation, wafer-scale fabrication and cost-effective manufacturing.

If these technical challenges can be further addressed, diamond could become a candidate material for high-voltage, high-temperature power electronics in areas such as aerospace, rail transportation, deep-earth exploration and other demanding environments.