Molecular beam epitaxy of high quality nitride semiconductors and fabrication of resonant tunneling diodes

摘要

The polarity control technology for Ga-polar GaN with molecular beam epitaxy using rf-plasma nitrogen source (RF-MBE) was established. Inserting high-temperature grown AlN multiple interlayers (FIT-AlN-MIL) into MBE-grown GaN at 750°C suppressed the propagation of dislocations into upper GaN, and the electrical and optical properties were improved. The HT-MN-M[L was deposited on GaN templates grown by metal organic chemical vapor deposition (MOCVD), followed by GaN grown by MBE. The dislocations with screw character in MBE-grown GaN were reduced by about two orders of magnitude compared to those of the bottom GaN template, which produced the step-like surface morphology for MBE-GaN. AlN/GaN double barrier resonant tunneling diodes (RTD) were fabricated by RF-MBE on MOCVD-GaN templates, using this dislocation reduction technique. Clear negative differential resistance with a peak-to-valley ratio over 30 has been obtained.