Ohmic contacts to buried n-GaInAs layers for GaInAs/AlInAs-HEMTs

The physical properties of the InP-based GaInAs/AlInAs system allow the fabrication of High-Electron-Mobility-Transistors (HEMTs) with superior device performance. However the full exploitation of material capabilities in such devices demands the reduction of parasitic elements like gate capacitance and series resistances. Their properties are strongly dependent on how the fabrication process is conducted. This paper focuses on the analysis of source and drain ohmic contacts, which have to provide a connection to the buried HEMT channel beneath a Si-doped GaInAs cap and a high bandgap AlInAs barrier layer.