Iii-N Transistor With Stepped Cap Layers

Brief Description

A new structure for III-N transistors that is able to maintain a high breakdown and operating voltage while improving the gain of the device.

Background

Traditional N-polar GaN deep recess HEMTs that are used for power amplication at mm-wave frequencies offer a high power density that is 4x larger than traditional Ga-polar HEMT structures. However, it is significantly smaller than the 40 W/mm of output power that has been demonstrated by other devices that use field plates. While field plates are known to increase voltage, they also require additional capacitances that ultimately limit the gain of the transistor making them less optimal. A structure that maximizes voltage while maintaining gain would significantly improve current transistors.

Description

Researchers at the University of California, Santa Barbara have created a new structure for III-N transistors that is able to maintain a high breakdown and operating voltage while improving the gain of the device. A stepped cap design is used to increase the operating voltage of the transistor and therefore provides a higher output power. Additionally, having a device that offers higher power allows for greatly simplified system level design due to the need for fewer parts to be combined. 

Advantages

• Increased breakdown voltage
• More reliable device operation
• Increased power allows for a simplified system with fewer parts

Applications

• GaN-Based Transistors
• Solid State Lighting

Patent Status