Growth And Characterization Of Gan/Aln Resonant Tunneling Diodes For High-Performance Nonvolatile Memory

GaN/AlN resonant tunneling diodes (RTDs) are studied to realize a high-speed nonvolatile memory based on the intersubband transactions and electron accumulation in the quantum well, which has the potential to operate at picosecond time scales. The crystal quality of GaN/AlN RTDs is improved by changing the growth conditions and structure of the buffer layer. The surface roughness and dislocation density of the GaN/AlN RTDs are successfully suppressed, and clear ON/OFF switching due to intersubband transitions is observed by inputting pulse voltage sequences. However, the voltages for write and erase operations are changed by improving the crystal quality of GaN/AlN RTDs. The theoretical analysis of resonant levels in the GaN/AlN RTDs indicates that the voltages for write and erase operations are very sensitive to the well and barrier widths and the density of electrons accumulating in the quantum well. Based on the results, the design of GaN/AlN RTDs for higher-performance nonvolatile memory operations is investigated.