Power Semiconductors

High voltage 20kV Aluminum Nitride (AlN) based Schottky diodes are being developed to demonstrate the high-voltage, high efficiency power conversion capability using low dislocation AlN substrates. For power systems and grid-scale power conversion applications, high efficiency AlN based power devices will offer a significant reduction in size, weight, and cooling. Compared to Silicon Carbide, AlN will provide a 10X improvement in performance.

Schottky Diode

High Voltage Power Conversion Market Opportunity

The global demand for energy savings through improved power conversion efficiency is creating a tremendous opportunity for high-performance power devices and innovative new power semiconductor technologies. The power grid is in the process of transforming to a system with distributed control to enable a plug and play structure requiring high voltage solid-state transformers to replace electromagnetic transformers. This new “internet for energy” will recognize and understand the different types of energy sources to maximize green energy utilization and allows the addition of storage and loads to the grid with no adverse effects. HexaTech AlN substrates will enable new high-voltage power semiconductors in the high-performance power device market.

Target Applications

•  Smart Grid Power
•  Rail Traction
•  Wind Turbine
•  Ship and Vessel Power Systems

Aluminum Nitride (AlN) Substrates Enable New High Voltage Power Electronics

AlN substrates are a transformational technology for high voltage power devices used in power conversion applications. These new products will enable substantial system cost and energy savings in power conversion applications at 10 kV and beyond. The device breakdown voltages will be up to 20 kV, offer high peak current capability, and have ultra-fast switching times for power switches and diodes. We plan to manufacture a portfolio of discrete power device components for our customers and provide access to our bulk AlN substrate material to customers for customized power device solutions.

Wide Bandgap Materials for Power Semiconductors – Comparing SiC and AlN

SiC is the state of the art today. AlN will enable power electronics with 10X SiC performance

Silicon carbide (SiC) power control devices are in development, and devices at the 10-20 kV level have been reported. However, SiC requires a very thick epitaxial structure, and as the voltage level becomes higher and higher the losses in these devices also increase significantly, limiting the device’s current handling capability. A semiconductor with drastically better materials properties is needed; one that will enable power electronics with the highest operating temperature, greatly reduced forward conduction losses and blocking voltage capability beyond 20 kV. High quality AlN offers the following advantages:

Metric State of the Art Proposed
Breakdown Field SiC AlN: 6x larger
Specific on-resistance
@ 10 kV breakdown
SiC AlN: 300x smaller
Required device area
(for same power level)
SiC AlN: 6x smaller

power conversion graphic

The property that makes AlN interesting for power devices is a very high critical electric field, which is related to achieving a high blocking voltage in the off-state. Both critical electric field and blocking voltage are strongly reduced by material with a high dislocation density, which necessitates very low dislocation density AlN wafers, to realize the exceptionally high critical field. AlN and AlGaN active regions of the devices will be grown epitaxial such that each layer inherits the high quality of the AlN substrate and preserves high critical field.