Maciej Matys

A nearly-ideal edge termination for GaN p–n junctions was designed and demonstrated using Mg-ions implanted field limiting rings (FLRs). The FLRs were fabricated via the ultra-high-pressure annealing process after implanting Mg-ions into the etched n-type region outside the main p–n junction. The results of the technology computer-aided design simulation indicate that by optimizing the space and width of the rings, the breakdown voltage (BV) can be increased by over 90% of the ideal parallel pla

Herein, we propose and demonstrate the edge termination for GaN-based one-sided abrupt p–n junctions. The structure is comprised of a combination of a shallow negative bevel mesa and selective-area p-type doping under the mesa. Based on the Technology Computer Aided Design (TCAD) simulation, the maximum electric field at the junction edge is markedly reduced to approximately 1.3 times that of the parallel-plane electric field in the proposed structure, which is almost half of the unimplanted dio

Vertical GaN junction barrier Schottky (JBS) diodes with superior electrical characteristics and nondestructive breakdown were realized using selective-area p-type doping via Mg ion implantation and subsequent ultra-high-pressure annealing. Mg-ion implantation was performed into a 10 μm thick Si-doped GaN drift layer grown on a free-standing n-type GaN substrate. We fabricated the JBS diodes with different n-type GaN channel widths Ln = 1 and 1.5 μm. The JBS diodes, depending on Ln, exhibited on

We investigated the excitation intensity (Φ) dependent photoluminescence (PL), at room temperature (RT), from GaN-based metal-insulator-semiconductor structures under gate bias (VG) from accumulation to deep depletion resulting in variations of the space charge region width. We found that depending on VG, different Φ-dependencies of the YL band energy position (blueshift or redshift), shape (band enlargement or narrowing) and intensity (signal saturation) can be obtained. In order to explain suc

The key feature for the precise tuning of Vth in GaN-based metal-insulator-semiconductor (MIS) high electron mobility transistors is the control of the positive fixed charge (Qf) at the insulator/III-N interfaces, whose amount is often comparable to the negative surface polarization charge (Qpol−). In order to clarify the origin of Qf, we carried out a comprehensive capacitance-voltage (C-V) characterization of SiO2/AlxGa1–xN/GaN and SiN/AlxGa1–xN/GaN structures with Al composition (x) varying f

Abstract In this review, we briefly summarize the major challenges and our recent progress in the development of GaN Junction Barrier Schottky (JBS) diodes using selective-area p-type doping with ion implantation and ultra high-pressure annealing (UHPA) process. As a starting point, we discuss the properties of Schottky contacts in the context of UHPA and provide design principle for a high performance JBS diode. Next, we propose a JBS diode having p-type regions formed by channeled ion implanta

We studied the drain current properties of an AlGaN/GaN multi-nano-channel (MNC) high electron mobility transistor (HEMT) fabricated on a sapphire substrate. We observed that the MNC HEMT exhibits the currents almost equal to those in the conventional planar device grown on the same chip. This result was unexpected since the actual gate width on the AlGaN surface in the case of MNC HEMT was only 20% of that for the planar device. In order to explain our experimental results, we performed a three

Herein, the observation of extremely high‐density (>10 14 cm −2 ) 2D electron gas (2DEG) in N‐polar AlGaN/GaN heterostructures grown on sapphire substrates is reported on. Due to introducing the GaN/AlN superlattice (SL) back barrier between the GaN buffer layer and AlGaN barrier layer, a giant enhancement of the 2DEG density is observed at the GaN/AlGaN interface from 3 × 10 13 cm −2 (without SL) to 1.4 × 10 14 cm −2 (with SL back barrier) that is only one order of magnitude below the intrin

The essential device for optical computing is an all-optical transistor in which a weak “gate” light controls the strong “source” light. Particularly promising for application in logic operations are all-optical transistors using quasiparticles in a semiconductor because they can be easily integrated into circuits in a way similar to that of conventional electronic ones. However, the practical development of such devices has so far been limited due to extreme difficulties in achieving room tempe

The AlGaN/GaN quantum-well heterostructures typically exhibit a positive photoconductivity (PPC) during the light illumination. Surprisingly, we found that introducing the GaN/AlN superlattice (SL) back barrier into N-polar AlGaN/GaN quantum-well heterostructures induces a transition in these heterostructures from PPC to negativie photoconductivity (NPC) as the SL period number increased at room temperature. This transition occurred under an infrared light illumination and can be well explained

We reported on the observation of extremely high-density ($>10^{14}$cm$^{-2}$) 2D electron gas in N-polar AlGaN/GaN heterostructures grown on sapphire substrates. Due to introducing the GaN/AlN superlattice (SL) back barrier between the GaN buffer layer and AlGaN barrier layer, we observed a giant enhancement of the 2D electron gas density at the GaN/AlGaN interface from $3\times10^{13}$cm$^{-2}$ (without SL) to $1.4\times10^{14}$cm$^{-2}$ (with SL back barrier) that is only one order of magn