GaN-Based Super Heterojunction Field Effect Transistors Using the Polarization Junction Concept

GaN super heterojunction field effect transistors (super HFET) based on the polarization junction concept are demonstrated for the first time. The super HFET has charges of 2-D electron gas and hole gas, respectively induced by positive and negative polarization charges at GaN/AlGaN/GaN heterointerfaces. Analogous to the RESURF concept, these unintentionally doped positive and negative polarization charges compensate each other in the off state condition to enhance the breakdown capability of the super HFET. The super HFETs have been fabricated on sapphire substrates and the electrical measurements show breakdown voltages over 1.1 kV with specific on-resistance of 6.1 mΩ· cm^2.