Vertical Diodes Research Articles

Vertical GaN-on-GaN Schottky Barrier Diodes With Multi-Floating Metal Rings

Vertical GaN Schottky barrier diodes (SBDs) with floating metal rings (FMRs) as edge termination structures have been fabricated on bulk GaN substrates. Devices with different FMR geometries were investigated including various numbers of rings and various spacings between rings. These devices have a low Ron of 1.16~1.59 mΩ·cm 2 , a turn-on voltage of 0.96~ 0.94 V, a high on-off ratio of 10 9 , a nearly ideal ideality factor of 1.03~1.09, and a Schottky barrier height of 1.11~1.18 eV at room temperature. These devices have similar forward electrical characteristics, indicating that FMRs don't degrade the device rectifying performance. The ideality factor decreased and the Schottky barrier height increased with increasing temperature from 300 K to 420 K, where the temperature dependencies of the two parameters indicate the inhomogeneity of the metal/semiconductor Schottky interface. In addition, FMRs can improve device breakdown voltages. As the number of FMRs increased from 0 to 20, the reverse breakdown voltage increased from 223 to 289 V. As the spacing between the FMRs increased from 1.5 to 3 μm, the reverse breakdown voltage increased from 233 to 290 V, respectively. These results indicate multiple FMRs with proper spacings can effectively improve breakdown performance without degrading the device forward characteristics. This work represents a useful reference for the FMR termination design for GaN power devices.

Temperature dependent characteristics of Ni/Au vertical Schottky diode based on mechanically exfoliated beta-Ga<sub>2</sub>O<sub>3</sub> single crystal

In this paper, a Ni/Au vertical structure Schottky diode based on mechanically exfoliated β-Ga<sub>2</sub>O<sub>3</sub> is fabricated. The temperature dependent characteristics of <i>I</i>-<i>V</i> curves are measured. The device shows a good rectifying behavior. As the temperature increases from 300 K to 473 K, the barrier height increases from 1.08 eV to 1.35 eV, and the ideal factor decreases from 1.32 to 1.19. Both of them show strong temperature dependence, which indicates that the Schottky barrier of the device is inhomogeneous. The device has a double exponential forward I-V characteristic curve, which may be related to crystal defects, surface states, surface energy band bending and the effect of mechanical exfoliation from the crystal surface. Through Cheung's method and Norde's method, the series resistances and barrier heights of the device at different temperatures are extracted. It is found that the parameters extracted by the Norde's method are in good agreement with the values obtained from the forward <i>I</i>-<i>V</i> curve. The series resistance decreases with temperature increasing, which is mainly caused by the increase of the concentration of thermally excited carriers. In this paper, the temperature characteristics of the device are modified by the Gauss distribution of the barrier height. The corrected barrier height is 1.54 eV and Richardson's constant is 26.35 A·cm<sup>–2</sup>·K<sup>–2</sup>, which is closer to the theoretical value. It shows that the <i>I</i>-<i>V</i> temperature characteristics of Au/Ni/β-Ga<sub>2</sub>O<sub>3</sub> Schottky diodes can be described by the thermionic emission model of the Gauss distribution barrier height accurately. There are a lot of surface states on the surface of Ga<sub>2</sub>O<sub>3</sub> single crystal obtained by Mechanical exfoliation, which has a great influence on the Schottky contact of the device and may lead to the inhomogeneity of Schottky barriers. At the same time, due to mechanical exploiation, the surface of gallium oxide single crystal material is not completely continuous, and the single crystal surface has layered or island structure. This will also cause the inhomogeneous Schottky barrier height. Considering the influence of inhomogeneous barrier on Schottky diode, the method of measuring the temperature characteristics is more suitable to extracting the electrical parameters of β-Ga<sub>2</sub>O<sub>3</sub> Schottky diodes than the method of fitting <i>I</i>-<i>V</i> forward curve by TE model.

Improved breakdown voltage in vertical GaN Schottky barrier diodes on free-standing GaN with Mg-compensated drift layer

Vertical Schottky barrier diodes (SBD) were fabricated on 1a 5 μm thick GaN drift layer (DL) with and without Mg-compensation grown by metal organic chemical vapour deposition on free-standing hydride vapour phase epitaxy grown substrate. The SBDs with Mg-compensated DL exhibited ∼3.4 × higher breakdown voltage (Vbd) than the SBDs with conventional DL. The activation energy of 0.43 eV from the SBD with Mg-compensated DL can be correlated to the presence of Mg. The reverse current conduction mechanism of SBDs with Mg-compensated DL and conventional DL was dominated by thermionic field emission (TFE) and barrier modified TFE, respectively.

Metal/BaTiO3/β-Ga2O3 dielectric heterojunction diode with 5.7 MV/cm breakdown field

Wide and ultrawide bandgap semiconductors can provide excellent performance due to their high energy bandgap, which leads to breakdown electric fields that are more than an order of magnitude higher than conventional silicon electronics. In materials where p-type doping is not available, achieving this high breakdown field in a vertical diode or transistor is very challenging. We propose and demonstrate the use of dielectric heterojunctions that use extreme permittivity materials to achieve a high breakdown field in a unipolar device. We demonstrate the integration of a high permittivity material BaTiO3 with n-type β-Ga2O3 to enable a 5.7 MV/cm average electric field and a 7 MV/cm peak electric field at the device edge while maintaining forward conduction with relatively low on-resistance and voltage loss. The proposed dielectric heterojunction could enable improved design strategies to achieve theoretical device performance limits in wide and ultrawide bandgap semiconductors where bipolar doping is challenging.

Vertical Field Emission Air-Channel Diodes and Transistors.

Vacuum channel transistors are potential candidates for low-loss and high-speed electronic devices beyond complementary metal-oxide-semiconductors (CMOS). When the nanoscale transport distance is smaller than the mean free path (MFP) in atmospheric pressure, a transistor can work in air owing to the immunity of carrier collision. The nature of a vacuum channel allows devices to function in a high-temperature radiation environment. This research intended to investigate gate location in a vertical vacuum channel transistor. The influence of scattering under different ambient pressure levels was evaluated using a transport distance of about 60 nm, around the range of MFP in air. The finite element model suggests that gate electrodes should be near emitters in vertical vacuum channel transistors because the electrodes exhibit high-drive currents and low-subthreshold swings. The particle trajectory model indicates that collected electron flow (electric current) performs like a typical metal oxide semiconductor field effect-transistor (MOSFET), and that gate voltage plays a role in enhancing emission electrons. The results of the measurement on vertical diodes show that current and voltage under reduced pressure and filled with CO2 are different from those under atmospheric pressure. This result implies that this design can be used for gas and pressure sensing.

High-Voltage ($\overline{\text{2}}01$ ) $\beta$ -Ga2O3 Vertical Schottky Barrier Diode With Thermally-Oxidized Termination

In this letter, a high-performance ( $\overline {{2}} 01$ ) $\beta $ -Ga2O3 vertical Schottky Barrier Diode (SBD) with a thermally oxidized termination is reported. A novel edge termination at the Schottky contact edge is formed by using thermal oxidation treatment, which reduces the electron concentration and effectively suppresses the peak electric field. By using a thermal oxidation termination, the breakdown voltage ( ${V}_{\text {br}}$ ) of $\beta $ -Ga2O3 SBD increases from 380 V to 940 V, and the specific on-resistance ( ${R}_{\text {on,sp}}$ ) just increases from 2.9 $\text{m}\Omega \cdot $ cm2 to 3.0 $\text{m}\Omega \cdot $ cm2. Our device demonstrates a power figure of merit ( ${V}_{\text {br}}^{{2}}/{R}_{\text {on,sp}})$ as high as 295 MW/cm2. These results indicate that the thermally oxidized termination shows a new way to improve the breakdown characteristics of $\beta $ -Ga2O3 SBD.

A Reconfigurable Remotely Epitaxial VO2 Electrical Heterostructure.

The reconfigurability of the electrical heterostructure featured with external variables, such as temperature, voltage, and strain, enabled electronic/optical phase transition in functional layers has great potential for future photonics, computing, and adaptive circuits. VO2 has been regarded as an archetypal phase transition building block with superior metal-insulator transition characteristics. However, the reconfigurable VO2-based heterostructure and the associated devices are rare due to the fundamental challenge in integrating high-quality VO2 in technologically important substrates. In this report, for the first time, we show the remote epitaxy of VO2 and the demonstration of a vertical diode device in a graphene/epitaxial VO2/single-crystalline BN/graphite structure with VO2 as a reconfigurable phase-change material and hexagonal boron nitride (h-BN) as an insulating layer. By diffraction and electrical transport studies, we show that the remote epitaxial VO2 films exhibit higher structural and electrical quality than direct epitaxial ones. By high-resolution transmission electron microscopy and Cs-corrected scanning transmission electron microscopy, we show that a graphene buffered substrate leads to a less strained VO2 film than the bare substrate. In the reconfigurable diode, we find that the Fermi level change and spectral weight shift along with the metal-insulator transition of VO2 could modify the transport characteristics. The work suggests the feasibility of developing a single-crystalline VO2-based reconfigurable heterostructure with arbitrary substrates and sheds light on designing novel adaptive photonics and electrical devices and circuits.

Field-Plated Ga2O3 Trench Schottky Barrier Diodes With a BV2/$R_{\text{on,sp}}$ of up to 0.95 GW/cm2

We report the realization of field-plated vertical Ga2O3 trench Schottky barrier diodes (SBDs). The trench SBDs show significantly lower leakage current than regular SBDs. With employment of field plate, a breakdown voltage (BV) of 2.89 kV is achieved, which is ~ 500 V higher than those without field plate. Trench sidewall depletion is observed, and the average depletion width is extracted using an analytical model. The trench SBDs have a differential specific on-resistance ( $\text {R}_{\text {on,sp}}$ ) of 10.5 (8.8) $\text{m}\Omega ~\cdot {\mathrm {cm}}^{\text {2}}$ from DC (pulsed) measurements, which leads to a Baliga’s figure-of-merit ( ${\mathrm {BV}}^{{2}}/\text {R}_{\text {on,sp}}$ ) of 0.80 (0.95) GW/cm2— the highest among Ga2O3 power devices to date.

Dry and wet etching for β-Ga2O3 Schottky barrier diodes with mesa termination

We investigated dry and wet etchings of β-Ga2O3 and fabricated vertical Schottky barrier diodes (SBDs) with mesa termination using the optimal etching condition. Using an inductively-coupled plasma reactive-ion etching with a nickel-hard mask, a β-Ga2O3 (010) mesa structure with a smooth sidewall is obtained at an etching rate of 77 nm min−1 in BCl3/Cl2 mixture gas. By immersing β-Ga2O3 (001) vertical SBDs with mesa termination in hot phosphoric-acid solution, the specific on resistance and ideality factor of the SBDs are reduced to 0.91 mΩcm2 and 1.03, respectively. Current density at reverse bias is in good agreement with thermionic field emission model.

Monolithic integration of high-voltage thin-film electronics on low-voltage integrated circuits using a solution process

The performance of silicon complementary metal–oxide–semiconductor integrated circuits can be enhanced through the monolithic three-dimensional integration of additional device layers. For example, silicon integrated circuits operate at low voltages (around 1 V) and high-voltage handling capabilities could be provided by monolithically integrating thin-film transistors. Here we show that high-voltage amorphous oxide semiconductor thin-film transistors can be integrated on top of a silicon integrated circuit containing 100-nm-node fin field-effect transistors using an in-air solution process. To solve the problem of voltage mismatch between these two device layers, we use a top Schottky, bottom ohmic contact structure to reduce the amorphous oxide semiconductor circuit switching voltage. These contacts are used to form Schottky-gated thin-film transistors and vertical thin-film diodes with excellent switching performance. As a result, we can create high-voltage amorphous oxide semiconductor circuits with switching voltages less than 1.2 V that can be directly integrated with silicon integrated circuits. High-voltage amorphous oxide semiconductor thin-film transistors can be integrated on top of a silicon integrated circuit containing 100-nm-node fin field-effect transistors using an in-air solution process.

Breakdown Walkout in Polarization-Doped Vertical GaN Diodes

We demonstrate the avalanche capability and the existence of breakdown walkout in GaN-on-GaN vertical devices with polarization doping. By means of combined electrical and optical characterization, we demonstrate the following original results: 1) vertical p-n junctions with polarization doping have avalanche capability; 2) stress in avalanche regime induces an increase in breakdown voltage, referred to as breakdown walkout; 3) this process is fully-recoverable, thus being related to a trapping mechanism; 4) temperature-dependent measurements of the breakdown walkout identify $\text{C}_{N}$ defects responsible for this process; and 5) capacitance deep level transient spectroscopy (C-DLTS) and deep level optical spectroscopy (DLOS) confirm the presence of residual carbon in the devices under test. A possible model to explain the avalanche walkout is then proposed.

Designing ESD Protection Devices for Ultrafast Overvoltage Events

This article provides an understanding of the transient voltage overshoot physics observed with electro-static discharge (ESD) n-type, p-type, and n-type diffusions (NPN) bipolar devices through the use of calibrated technical computer-aided design (TCAD) with measured silicon results. This analysis graphically steps through each stage of the measured transient electrical response, to explain the inertia that limits the speed of the NPN ESD cell, and then uses this knowledge to provide a fully characterized silicon solution for ultrafast ESD events to achieve an 8-kV IEC61000-4-4 rating. This solution is developed by exploring five different integrated designs that are constructed on an 80-V bipolar and complimentary double-diffused metal-oxide semiconductor (BiCDMOS) process platform to protect against a product level 125-V voltage overshoot gate oxide ruptures as measured with a 0.6-ns rise time transmission line pulse (TLP). The fully characterized electrical results for each test overshoot structure with a fixed layout area of $200\,\,\mu \text{m}\,\,\times200\,\,\mu \text{m}$ , are in parallel to NPN ESD cells arranged with two in series and two in parallel ( $200\,\,\mu \text{m}\,\,\times 80\,\,\mu \text{m}$ ) and compared in terms of the current-carrying capability before the gate oxide rupture voltage of 125 V is reached. The results show that a diode engineered with a vertical breakdown achieves an ESD strength of 9.7 A before the overshoot voltage reaches the target of 125-V, resulting in a net 0.17 mA $\mu \text{m}^{-{2}}$ . The combined use of this vertical diode structure in parallel to the NPN ESD cell translates into a 7-A improvement in the strength of a conventional NPN for ultrafast timescales, which achieves the 8-kV International Electrotechnical Commission (IEC) ESD performance for this case study.

Near-junction heat spreaders for hot spot thermal management of high power density electronic devices

Many high power (opto-) electronic devices such as transistors, diodes, and lasers suffer from significant hot spot temperature rises due to the high heat fluxes generated in their active area, which limits their performance, reliability, and lifetime. Employing high thermal conductivity materials near the heat source, known as near-junction heat spreaders, offers a low-cost and effective thermal management approach. Here, we present analytical heat spreader models and a methodology to evaluate their performance. Experimental demonstration of near-junction diamond heat spreaders on vertical GaN PiN diodes revealed significantly reduced spreading resistances, along with very low temperature gradients across the device. The findings in this work provide design guidelines and demonstrate excellent prospects, especially for the devices on low thermal conductivity substrates. The theoretical analysis of optimized diamond heat spreaders shows an 86% reduction of spreading resistance for GaN devices and 98% for Ga2O3 devices. In addition, our results show that a 3 μm-thick layer of high-quality CVD-deposited diamond heat spreaders on GaN-on-Si devices can provide better heat spreading than GaN-on-SiC devices and perform similar to GaN-on-diamond devices, highlighting the significant potential of heat spreaders as an effective and low-cost thermal management approach.

Impact of defects on the electrical properties of p–n diodes formed by implanting Mg and H ions into N-polar GaN

The relationship between the junction properties and point defects in p–n diodes, formed by implanting magnesium (Mg) and hydrogen (H) ions into a GaN layer, was investigated. Vertical diodes were fabricated by implanting Mg ions with and without H ions into nitrogen-polar n-type GaN substrates, followed by annealing at 1150 °C or 1230 °C without the use of protective layers. Samples annealed at 1150 °C showed Schottky-barrier-diode (SBD)-like properties with an insufficient build-in potential, indicating surface depletion due to poor activation of Mg acceptors. The Mg/H-ion-implanted diode annealed at 1230 °C exhibited an improved rectifying property with a build-in potential around 3 V, close to an ideal p–n junction of GaN, whereas the sample with only implanted Mg-ions exhibited mixed properties of a p–n junction and SBD due to imperfect activation. In addition, leakage currents in the forward bias below 3 V for the Mg/H-ion-implanted diodes can be explained by a recombination current based on the Shockley–Read–Hall model with an estimated recombination lifetime of 3 to 10 ps. To clarify the sources of the difference in the junction properties, positron annihilation spectroscopy was employed. The samples annealed at 1150 °C contained high-density vacancy clusters such as (VGaVN)3, whose concentrations were reduced by the higher temperature annealing. We found that introduced H atoms can enhance the activation of Mg acceptors and/or reduce the defect concentrations. The results indicate the combination of the H ion introduction and higher temperature annealing improves the junction properties.

Vertical β‐Ga2O3 Schottky Barrier Diodes with Enhanced Breakdown Voltage and High Switching Performance

Herein, vertical Schottky barrier diodes (SBDs) based on a bulk β‐Ga2O3 substrate are developed. The devices feature an ion‐implanted planar edge termination (ET) structure, which can effectively smoothen the electric field peak and reduce the electric field crowding at the Schottky junction edge. Greatly enhanced reverse blocking characteristics including ≈103× lower reverse leakage current and 1.5× higher breakdown voltage (VB) are achieved, whereas good forward conduction such as a reasonably high on‐state current density and near‐unity ideality factor is maintained. In addition, the switching performance of the fabricated vertical β‐Ga2O3 SBDs is investigated using a double‐pulse test circuit. When switching from an on‐state current of 350 mA to a reverse‐blocking voltage of −100 V, the vertical β‐Ga2O3 SBDs exhibit fast reverse recovery with a reverse recovery time (trr) of ≈14.1 ns and reverse recovery charge (Qrr) of ≈0.34 nC, outperforming the Si fast recovery diode (FRD) of similar ratings. The results indicate a great promise of vertical β‐Ga2O3 SBDs for high‐voltage fast switching applications.

(Invited) Homoepitaxial GaN Growth and Substrate-Dependent Effects

Vertical GaN power switch technology is expected to be utilized in next-generation medium to high voltage power converters due to the low ON-resistance and high breakdown voltage enabled by the improved critical electric field and mobility compared to Si and SiC-based devices. As large area substrates have become available by hydride vapor phase epitaxy (HVPE) and ammonothermal growth, the properties of nitrides are no longer dominated by defects introduced by heteroepitaxial growth, allowing recent realization of several fundamental vertical power devices, including diodes with edge termination, trench MOSFETs, and CAVETs. However, additional materials challenges are coming to the forefront that need to be understood and surmounted in order to allow vertical GaN power devices to achieve their full potential, notably the realization of repeatable thick drift layers with low background doping. To enable this, a deeper understanding of substrate preparation and the effects of the substrate and growth initiation on the characteristics of the epitaxial layers is required for MOCVD growth of homoepitaxial films. We investigate these effects on epi morphology, uniformity, and impurity incorporation by growing simultaneously on wafers from different vendors. The goal of this work is to detect and identify defects in GaN substrates with a series of quick, non-destructive, inexpensive techniques with capabilities of mapping whole wafers. Four different substrates - three grown by hydride vapor phase epitaxy and the fourth by ammonothermal technique were obtained from multiple vendors. All had nominally similar as-received specifications (resistivity, thickness, off-cut angle, bow, surface finish). The substrates were evaluated with a variety of techniques including Raman spectroscopy, photoluminescence, white light interferometry, and Nomarski imaging, enabling to detection of different concentrations of grain boundaries, sample impurities, point defects, v-shaped pits, polishing defects, crystal stress damage, and non-uniform insulating and conducive regions. Comparing these results to those from homoepitaxial growth on the same wafers, the effects are both subtle and overt. Macroscopic surface morphology, which has shown a direct correlation to leakage current, copies and exaggerates that of the underlying substrate. Donor incorporation in the epitaxy is relatively uniform, regardless of the substrate doping. However, homoepitaxy on substrates with inhomogeneous impurity incorporation did show some near band edge broadening by PL. Carbon incorporation varied with substrate offcut angle, which is supported by DFT calculations. All interfaces between epitaxy and substrate have a large Si peak, which requires further study. Following optical characterization, vertical Schottky diodes were fabricated to quickly evaluate device performance. While most of the films showed the ability to withstand high electric fields, those with more uniform properties in the substrate also showed more uniform electrical properties. These results show that the bulk substrates enable the path to high voltage vertical devices, but also show the significant influence that substrates can play in device performance.

Vertical Ga2O3 Schottky Barrier Diodes With Guard Ring Formed by Nitrogen-Ion Implantation

A guard ring (GR) was employed to improve the breakdown voltage ( ${V}_{\text {br}}$ ) of vertical Ga2O3 Schottky barrier diodes (SBDs) with or without a field-plate (FP) by eliminating electric field concentration at the edges of anode and FP electrodes. The GR structure was formed by nitrogen (N)-ion implantation. Four types of vertical SBD structures with: 1) neither a GR nor a FP; 2) a GR; 3) a FP; and 4) both a GR and a FP were fabricated on the same substrate. The SBDs with a GR [structures 2) and 4)] showed larger ${V}_{\text {br}}$ values than their GR-free counterparts [structures 1) and 3)]. Considering the trade-off relationship between ${V}_{\text {br}}$ and specific on-resistance ( ${R}_{\text {on}}$ ), a ${V}_{\text {br}}/{R}_{\text {on}}$ combination of 1.43 kV/ $4.7~\text {m}\Omega \cdot \text {cm}^{2}$ for the GR/FP-SBD corresponds to one of the best balanced data for Ga2O3 SBDs.

Vertical Ga2O3Schottky Barrier Diodes With Small-Angle Beveled Field Plates: A Baliga’s Figure-of-Merit of 0.6 GW/cm2

This letter demonstrates vertical Ga2O3 Schottky barrier diodes (SBDs) with a novel edge termination, the small-angle beveled field plate (SABFP), fabricated on thinned $\text{G}_{{2}}\text{O}_{{3}}$ substrates. Non-punch-though design is used for the drift region with a donor concentration of ${3}\sim {3.5} \times {10} ^{{16}}$ cm−3, rendering a device differential ON-resistance of $\sim 2~\text{m}\Omega ~\cdot $ cm2. A new wet-etch technique is developed by using a bi-layer mask, which consists of spin-on-glass (SOG) and plasma-enhanced chemical vapor deposited (PECVD) SiO2, to fabricate a very small bevel angle (∼ 1°) in the mesa and field plates. This SABFP structure facilitates the electric field spreading at device edges, rendering a breakdown voltage of 1100 V, a peak electric field of 3.5 MV/cm in Ga2O3 at the Schottky contact edge, and an averaged electric field over 3.4 MV/cm underneath the contact. Our device demonstrates a Baliga’s figure of merit of 0.6 GW/cm2, which is among the highest in all reported Ga2O3 power devices and comparable to the state-of-the-art GaN SBDs. These results show the great potential of Ga2O3 SBDs for future power applications.

(Invited) Defects and Development of High Power Vertical GaN Based Structures

This presentation highlights the use of x-ray scattering and electron microscopy to characterize selectively doped GaN layers for high power vertical diodes. Examples from these techniques will include assessment of residual impurities and crystalline damage in selectively doped regions resulting from dry etching or ion implantation processes and if such defects are removed by subsequent etching and / or annealing steps. X-ray reflectivity (XRR) combined with high angle reciprocal space mapping and dynamical diffraction simulations are effective means by which to assess the strain and defect distribution in the wafers. Advanced synchrotron techniques, through the use of hard x-ray nanoprobes and diffraction imaging, offer further insight into the development of these technologies. Transmission Electron Microscopy measurements, including electron energy loss spectroscopy, energy dispersive x-ray analysis, and selected area diffraction patterns, determine whether impurities were introduced by the selective doping process and whether the damage removal processes were able to remove growth and implantation-induced defects. A better understanding of the roles of defects on device performance is based on these techniques.

The further investigation of N-doped β-Ga2O3 thin films with native defects for Schottky-barrier diode

The structural, electronic and optical properties of β-Ga2O3 thin films with different N ion concentrations are investigated. With N concentrations increasing, the crystallization degrades and even polycrystalline appears. After Ar annealing treatment, the crystallization of N-doped β-Ga2O3 thin films improved owing to recovery of the implantation-damaged crystals. The N-doped Ga2O3 thin films were used to construct vertical Schottky diodes comprising Ga2O3:N/n-Ga2O3. The net carrier concentrations of these devices degrade one-two orders due to the compensation effect of more N implantation, which suggests that hole could be mobile although N is a deep acceptor dopant. The phenomenon could be explained by the decrease of the ionization energy of N dopant due to the complex defects NGa2O3VO (N-doped β-Ga2O3 with O vacancy) and NGa2O3VGa (N-doped β-Ga2O3 with Ga vacancy). Thus, the development of N ion implantation for β-Ga2O3 has its potential opportunity for β-Ga2O3 power devices.