High electron mobility transistor and methode of making
AssigneeHughes Aircraft Company
InventorMarko Sokolich
Life of this patent
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Abstract
A high electron mobility transistor (HEMT) includes a diffusion barrier (22) to prevent gate metal (20) diffusion into the substrate (12) during fabrication and a sacrificial platinum alloy layer (30) forms the Schottky barrier. A method of forming a HEMT includes forming a diffusion barrier of titanium nitride on a platinum layer and applying sufficient heat to cause the platinum layer to alloy with the gallium arsenide layer forming a platinum gallium and platinum arsenide alloy layer and Schottky barrier. Since all platinum is consumed, this method permits precise control of the thickness of the gate layer and eliminates diffusion of the platinum gate layer into the gallium arsenide layer during later processing steps.
Claims4
A high electron mobility transistor (HEMT), comprising:
- a current carrying active layer formed of an epitaxial layer of gallium arsenide (GaAs) on a semi-insulating substrate, the active layer including source and drain regions;
- a gate layer of aluminum gallium arsenide (AlGaAs) on the active layer;
- a Schottky barrier layer on the gate layer, the Schottky barrier layer being formed of a metal alloy comprising platinum gallium (PtGa) and platinum arsenide (PtAs);
- a diffusion barrier layer of titanium nitride (TiN) on the Schottky barrier;
- and
- ohmic contacts formed on the gate, source and drain regions.
Dependencies are inferred from the claim text.