EPC eGaN is grown on Silicon with an Aluminum Nitride Isolation Layer. AlGaN is grown on top of the GaN which creates a strain in the lattice that causes electrons to “pool” at this  interface. These electrons have a very high mobility, creating what is known as a High Electron Mobility Transistor (HEMT). This structure enables very efficient conduction and high frequency operation. A proprietary process was developed that depletes the electrons under the gate thus forming a normally off device that behaves very similarly to a silicon, N-channel, enhancement mode MOSFET. They are bidirectional, three terminal devices, designated as Drain, Source and Gate. Enhancement mode transistors are off with zero or negative voltage from the gate relative to the source. A positive voltage on the gate turns it on with a resistive characteristic. There is no physical diode that bypasses the switch in the reverse direction, however, when current is forced from source to drain, the drain voltage falls to the point where it begins to turn the channel on, acting just like a diode. As no minority carriers are present, these devices have no reverse recovery. While there have been many “exotic” materials used for advanced transistors, their acceptance has been limited by the expense of the starting material and the cost of non-standard processing. With silicon as the starting material, and GaN requiring similar processing conditions as silicon, existing CMOS foundries can be used to produce a fundamentally cost effective device with loads of available capacity.