GaN power device and manufacturing method thereof

A method for manufacturing a gallium nitride (GaN) power device, comprising:

• obtaining a basic structure of the GaN power device, wherein the basic structure comprises a substrate, a buffer layer, a GaN channel layer and a barrier layer stacked in sequence from bottom to top;
• depositing a p-GaN epitaxial layer on the barrier layer of the basic structure;
• etching the p-GaN epitaxial layer to form a p-GaN thin layer and a p-GaN cap layer connected to the p-GaN thin layer on an upper surface of the barrier layer;
• providing a control electrode on the p-GaN cap layer, and providing an input electrode and an output electrode on the upper surface of the barrier layer;
• wherein the control electrode and the p-GaN thin layer are located between the input electrode and the output electrode;
• wherein the GaN power device is an enhancement mode GaN high electron mobility transistor (HEMT) device;
• one electrode of a drain electrode and a source electrode of the enhancement mode GaN HEMT device is configured to correspond to the input electrode, and the other electrode of the source electrode and the drain electrode of the enhancement mode GaN HEMT device is configured to correspond to the output electrode;
• a gate electrode of the enhancement mode GaN HEMT device is configured to correspond to the control electrode;
• the p-GaN thin layer is provided between the gate electrode and the drain electrode;
• and holes are provided inside the p-GaN thin layer:
• in response to that no bias voltage is applied to the gate electrode, no two-dimensional electron gas exists beneath the p-GaN cap layer and the p-GaN thin layer;
• the p-GaN cap layer and the p-GaN thin layer are configured to deplete the two-dimensional electron gas in the area covered by the p-GaN cap layer and the p-GaN thin layer to make the GaN power device appear in an off state without external bias voltage;
• and
• in response to that a bias voltage is applied to the gate electrode, two-dimensional electron gas exists beneath the barrier layer beneath the p-GaN cap layer and the p-GaN thin layer.