Group III-V device structure

A group III-V device structure, comprising:

• a channel layer formed over a substrate;
• an active layer formed over the channel layer;
• a doped structure formed over the active layer;
• a first dielectric layer formed over the active layer and covering an edge of the doped structure;
• a gate electrode formed over the doped structure, wherein the first dielectric layer has a first portion, the first portion of the first dielectric layer covers the doped structure, and the gate electrode covers the first portion of the first dielectric layer;
• a through via structure extending from the first dielectric layer to a portion of the substrate;
• a conductive layer formed over the through via structure, wherein a top surface of the gate electrode is higher than a top surface of the conductive layer, wherein a top surface of the conductive layer is level with a top surface of the first portion of the first dielectric layer;
• and
• a doped well region formed in a portion of the substrate and below the through via structure, wherein the doped well region surrounds a bottom portion of the through via structure, the doped well region is doped with a first conductivity type, the substrate is doped with a second conductivity type, and the first conductivity type is different from the second conductivity type.

A group III-V device structure, comprising:

• a channel layer formed over a substrate;
• an active layer formed over the channel layer;
• a p-doped layer formed over the active layer;
• a n-doped layer formed over the p-doped layer;
• a first dielectric layer formed over the active layer;
• a gate electrode formed over the n-doped layer, wherein the gate electrode is in direct contact with the n-doped layer;
• a source electrode formed adjacent to the gate electrode, wherein the source electrode has an extending portion, and the extending portion of the source electrode covers a top surface of the first dielectric layer, and a top surface of the source electrode is level with a top surface of the first dielectric layer;
• a through via structure formed in the substrate, wherein the extending portion of the source electrode extends over the through via structure, and
• a doped well region formed in a portion of the substrate and below the through via structure, wherein the doped well region surrounds a bottom portion of the through via structure.