▎ 摘　　要

NOVELTY - The transistor has an epitaxial layer (20) provided a first semiconductor layer and a second semiconductor layer disposed on the first semiconductor layer. A drain metal and a gate metal are disposed on the epitaxial layer in a spaced and insulated manner. A first semiconductor structure (30) is disposed on the epitaxial layer and located on a side of the gate metal close to a substrate (10), and connected to the gate metal. A second semiconductor structure (40) is disposed on the epitaxial layer between the drain metal and the second semiconductor layer and connected to the drain metal. A conductive graphene layer (50) is disposed between the gate metal and the first semiconductor structure, and disposed opposite to the gate metal, and/or disposed between the second semiconductor structure and the second semiconductor layer, and disposed opposite to the second semiconductor structure. Both the first semiconductor layer and the second semiconductor layer are group III nitrides. USE - High electron mobility transistor in semiconductor device. ADVANTAGE - The transistor inhabits the active magnesium ions of the first semiconductor structure from diffusing to the gate metal by setting the conductive graphene layer, thus reducing the leakage of the gate metal, improves the stability of the gate metal, and presses the diffusion of active magnesium ions in the second semiconductor structure to the second semiconductor layer, thus improving the forward conducting and reverse blocking characteristics of the drain metal. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a preparation method of high electron mobility transistor in semiconductor device. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the high electron mobility transistor. 10Substrate 20Epitaxial layer 21Buffer layer 22First semiconductor layer 23Second semiconductor layer 30First semiconductor structure 40Second semiconductor structure 50Conductive graphene layer 51First conductive graphene layer 52Second conductive graphene layer 60Gate metal 70Drain metal 80Source metal 100High electron mobility transistor 101Gate structure 102Drain structure