Negative differential resistance characteristics of GaN-based resonant tunneling diodes with quaternary AlInGaN as barrier

Abstract

AlInGaN lattice-matched to GaN is proposed as a barrier for double-barrier single quantum well structure resonant tunneling diodes (RTDs), and it achievesnearly strain-free RTD with low In composition and thereby relatively high manufacturability. Compared with the lattice-matched ternary Al0.83In0.17N/GaN RTD, three lattice-matched InAlGaN/GaN RTD samples exhibit peak current density J P over 20 times larger than that of the lattice-matched ternary RTD in numerical simulations. Simultaneously, two shallow defect levels (E 1 = 0.351 eV, E 2 = 0.487 eV) are considered at the RTD heterointerface to reveal the I–V characteristics under different defect densities. Negative differential resistance characteristics of the three quaternary RTDs are still available even though the defect density is up to ∼1018 cm−3, while that of the lattice-matched ternary RTD almost disappears when the defect density is ∼1017 cm−3 as a result of the lager ionization rate. Further, we introduce a deep-level defect E t = 1 eV at the heterointerface and perform multiple forward voltage sweeps. Simulations show that the quaternary RTD samples have better reproducibility in spite of the defect density being 100 times larger than that of the lattice-matched ternary RTD. This work illustrates that InAlGaN can provide greater flexibility for the design and fabrication of GaN-based RTDs.

Enhancement of nonvolatile memory characteristics caused by GaN/AlN resonant tunneling diodes

“…In addition, the reason that the NDR cannot be observed experimentally at 0.1 V, −0.1 V, −1.6 V, etc is the relatively large roughness of the GaN/AlN heterointerfaces fabricated by MOVPE [26,27]. If an extremely small roughness in the heterostructures can be realized by a different growth technique such as molecular beam epitaxy, NRDs would be observed in the I-V characteristics, as reported elsewhere [21][22][23][24][25][29][30][31][32][33].…”

“…In addition, this memory has been confirmed to achieve high-repetition nonvolatile-memory-operation (>10 5 cycles), a long retention time (>30 h) and low write and erase voltages (<2 V) [7,8]. These continuous studies have enabled us to apply GaN/AlN RTDs to nonvolatile memories in addition to terahertz oscillators [21][22][23][24][25][26][27][28][29][30][31][32][33].…”

“…Therefore, the improvement of quantum well structure, considering the dipole moment and E DL and E ′ DL , is necessary to decrease the erase voltages. The use of different materials-based barrier layers, such as AlGaN and AlInGaN barrier layers, might be effective in solving this problem, because they have a potential to change the strength of spontaneous and piezo polarizations in quantum well structure and z-direction energy of deep levels in barrier layers [30,47].…”