Integrated circuit with matching threshold voltages and method for making same

An integrated circuit comprising:

• a substrate;
• at least one buffer layer formed over the substrate;
• a GaN channel layer formed over the at least one buffer layer;
• a barrier layer formed over the GaN channel layer;
• and
• an isolation region that isolates a first portion of the barrier layer for a first transistor device from a second portion of the barrier layer for a second transistor device, the first and second portions of the barrier layer each having respective gate contact recesses;
• a first gate contact disposed at least partially in the gate contact recess of the first portion of the barrier layer for the first transistor device;
• and
• a second gate contact disposed at least partially in the gate contact recess of the second portion of the barrier layer for the second transistor device.