Folded channel gallium nitride based field-effect transistor and method of manufacturing the same

A folded channel gallium nitride based field-effect transistor, comprising:

• a base layer, comprising a nitride buffer layer and a gallium nitride semi-insulating layer formed sequentially on a substrate from bottom to top, wherein a channel region comprising at least one parallel extended groove is formed on an upper surface of the gallium nitride semi-insulating layer;
• a multi-heterojunction layer, comprising a channel layer and a barrier layer alternatingly stacked from bottom to top on the gallium nitride semi-insulating layer, wherein a heterojunction is formed between the barrier layer and the channel layer that are adjacent;
• a gallium nitride control layer on the multi-heterojunction layer and extending from one side of the channel region to at least a part of the groove, so as to adjust a charge balance within the channel region corresponding to on and off states of the field-effect transistor;
• a current collapse suppression structure formed on the multi-heterojunction layer on another side of the channel region and separated from the gallium nitride control layer by another part of the groove, wherein the current collapse suppression structure is applicable to provide, when a voltage of a drain electrode is high, a hole injection to the drain electrode, so that a charge balance on the drain electrode is achieved;
• a source electrode and the drain electrode that are respectively in contact with two sides of the multi-heterojunction layer on the gallium nitride semi-insulating layer, wherein the drain electrode is in contact with a side surface of the current collapse suppression structure and a part of an upper surface of the current collapse suppression structure;
• a gate electrode formed on the multi-heterojunction layer between the source electrode and the gallium nitride control layer;
• and
• a connecting structure passing over the gate electrode to electrically connect to the source electrode and the gallium nitride control layer.