Research On InP-Based AlAs/In_0.53Ga_0.47As Resonant Tunning Diode

Resonant tunneling diode (RTD) which is based on resonant tunneling quanta effect is a new two-terminal device with high speed. It has been widely used in multi-state memory, A/D converter, multi-value logic, frequency divider, double frequency and so on. Because RTD has rapidly development and excellent foreground of application, study on RTD become more urgently.In this paper, InP material system RTD that has better characteristics was researched. Through improving structure material epitaxy process and device fabrication process, the first internal InP based AlAs /In_0.53Ga_0.47As RTD were fabricated successfully.First, RTD with structure of AlAs/In_0.53Ga_0.47As/AlAs double barriers signal well was brought based on the principle of resonant tunneling diode and relative characteristic of InP based material. AlAs was selected as barrier because it has wide energy band which can reduce the affection of scatter effectively and improve peak-to-valley ratio (PVCR). Crystal lattices of In_0.53Ga_0.47As and InP match completely that can improve growth quality of epitaxy layer. Growth condition was optimized by trial and error, and better growth temperature and growth rate were confirmed, then material structure of RTD was grown by molecular beam epitaxy. (001) semi-insulation InP substrate was chosen, and epitaxy growth was done on it. Epitaxy growth was disconnected in the heterogeneity interface to improve quality of the interface. During the epitaxy, growth state of surface was observed by reflected high energy electronic diffraction (RHEED) to make tiny adjustment. Test was done on the finished epitaxy wafer by X-ray double-crystal diffraction instrument and PL spectrum, result was coincident with the design. Mesa structure was used for fabrication of RTD device, Ohm contact of emitter and collector use AuGeNi, and inner wore use TiPtAu. In the end, DC characteristics of the fabricated device were tested at room temperature. Results are as follows: Peak-to-valley current ratio (PVCR) is 7.4, and peak current density (JP) is 1.06×10⁵A/cm².