Group III nitride-based monolithic microwave integrated circuits having multi-layer metal-insulator-metal capacitors

A radio frequency (“RF”) transistor amplifier, comprising:

• a Group III nitride based semiconductor layer structure;
• a first metal layer that is on an upper surface of the Group III nitride based semiconductor layer structure, wherein a plurality of gate fingers of the RF transistor amplifier and a lower electrode of a first capacitor are part of the first metal layer;
• a first dielectric layer that is directly on an upper surface of the first metal layer;
• a second metal layer that is directly on an upper surface of the first dielectric layer, wherein a plurality of drain fingers of the RF transistor amplifier and an upper electrode of the first capacitor that also serves as a lower electrode of a second capacitor are part of the second metal layer;
• a second dielectric layer that is directly on an upper surface of the second metal layer;
• and
• a third metal layer that is directly on an upper surface of the second dielectric layer, wherein an upper electrode of the second capacitor is part of the third metal layer,
• wherein the second capacitor is stacked on top of the first capacitor to form a multi-layer capacitor structure.

A semiconductor device, comprising:

• a first metal layer that is on an upper surface of the Group III nitride based semiconductor layer structure, wherein a lower electrode of a first capacitor is part of the first metal layer;
• a first dielectric layer that is directly on an upper surface of the first metal layer;
• a second metal layer that is directly on an upper surface of the first dielectric layer, wherein an upper electrode of the first capacitor that also serves as a lower electrode of the second capacitor is part of the second metal layer;
• a second dielectric layer that is directly on an upper surface of the second metal layer, the second dielectric layer having a stepped upper surface and at least one sidewall connecting adjacent portions of the stepped upper surface;
• a third dielectric layer directly on the sidewall of the second dielectric layer;
• a third metal layer that is directly on an upper surface of the second dielectric layer and directly on an upper surface of the third dielectric layer, wherein an upper electrode of the second capacitor is part of the third metal layer,
• wherein the third dielectric layer is stacked directly on the upper surface of the second dielectric layer and the second dielectric layer is stacked directly on the upper surface of the first dielectric layer adjacent a sidewall of the second metal layer.