Cap Layers Including Aluminum Nitride for Nitride-Based Transistors and Methods of Fabricating Same

A Group III-nitride high electron mobility transistor (HEMT), comprising:

• a Group III-nitride based channel layer;
• a Group III-nitride based barrier layer on the channel layer;
• and
• a multilayer cap layer on the barrier layer, the multilayer cap layer including an aluminum gallium nitride (AlGaN) layer on the barrier layer and an aluminum nitride (AlN) layer on the AlGaN layer.

A Group III-nitride high electron mobility transistor (HEMT), comprising:

• a Group III-nitride based channel layer;
• a Group III-nitride based barrier layer on the channel layer;
• and
• a multilayer cap layer on the barrier layer, the multilayer cap layer including an aluminum gallium nitride (AlGaN) layer on the barrier layer, an aluminum nitride (AlN) layer on the AlGaN layer and a gallium nitride (GaN) layer on the AlN layer.

A method of forming a Group III-nitride high electron mobility transistor (HEMT), comprising:

• forming a Group III-nitride based channel layer;
• forming a Group III-nitride based barrier layer on the channel layer;
• forming a multilayer cap layer on the barrier layer, the multilayer cap layer including a layer including aluminum nitride (AlN) on the barrier layer and a gallium nitride (GaN) layer on the layer including AlN;
• and
• forming a SiN passivation layer on the GaN layer.

A method of forming a Group III-nitride high electron mobility transistor (HEMT), comprising:

• forming a Group III-nitride based channel layer;
• forming a Group III-nitride based barrier layer on the channel layer;
• and
• forming a multilayer cap layer on the barrier layer, the multilayer cap layer including an aluminum gallium nitride (AlGaN) layer on the barrier layer and an aluminum nitride (AlN) layer on the AlGaN layer.

A method of forming a Group III-nitride high electron mobility transistor (HEMT), comprising:

• forming a Group III-nitride based channel layer;
• forming a Group III-nitride based barrier layer on the channel layer;
• and
• forming a multilayer cap layer on the barrier layer, the multilayer cap layer including an aluminum gallium nitride (AlGaN) layer on the barrier layer, an aluminum nitride (AlN) layer on the AlGaN layer and a gallium nitride (GaN) layer on the AlN layer.