Terminal Structure Research Articles

Household salt production by the Late Classic Maya: underwater excavations at Ta'ab Nuk Na

Salt is an essential commodity; archaeological remains around the world attest to the importance of its production, exchange and consumption. Often located in coastal locations, many production sites were submerged by rising seas, including the Paynes Creek Salt Works on the southern Belize coast. Survey and excavation of these sites has identified ‘kitchens’ for brine boiling, as well as Terminal Classic residential structures at Ek Way Nal. The authors report the discovery of an earlier residential building alongside salt kitchens at the nearby site of Ta'ab Nuk Na. This finding indicates that surplus household production began during the Late Classic, when demand for salt from inland cities was at its peak.

Suppression of nonideal leakage current in a-InGaZnO Schottky diode with edge termination structures

The nonideal reverse leakage current of amorphous indium-gallium-zinc-oxide (a-IGZO) Schottky barrier diode was comparatively investigated with and without the passivation layer. Based on experimental and simulation results, the underlying mechanism was revealed as the trap-assisted tunneling along the defective a-IGZO sidewall. The edge termination structures, dubbed “sidewall covering,” and “edge capping” were specifically proposed to mitigate the edge electric field and, thus, suppress the nonideal leakage current. This enables the simultaneously improved ideality factor (n) and Schottky barrier height (ΦB), respectively, of 1.16 and 1.13 eV, together with the noticeably enhanced breakdown voltage.

A dedicated C-6 β-hydroxyacyltransferase required for biosynthesis of the glycolipid anchor for Vi antigen capsule in typhoidal Salmonella

Vi antigen is an extracellular polysaccharide produced by Salmonella enterica Typhi, Citrobacter freundii, and some soil bacteria belonging to the Burkholderiales. In Salmonella Typhi, Vi-antigen capsule protects the bacterium against host defenses, and the glycan is used in a current glycoconjugate vaccine to protect against typhoid. Vi antigen is a glycolipid assembled in the cytoplasm and translocated to the cell surface by an export complex driven by an ABC transporter. In Salmonella Typhi, efficient export and cell-surface retention of the capsule layer depend on a reducing terminal acylated-HexNAc moiety. Although the precise structure and biosynthesis of the acylated terminus has not been resolved, it distinguishes Vi antigen from other known glycolipid substrates for bacterial ABC transporters. The genetic locus for Vi antigen-biosynthesis encodes a single acyltransferase candidate (VexE), which is implicated in the acylation process. Here, we determined the structure of the VexE invitro reaction product by mass spectrometry and NMR spectroscopy to reveal that VexE catalyzes β-hydroxyacyl-ACP dependent acylation of the activated sugar precursor, uridine-5'-diphospho-GlcNAc, at C-6 to form UDP-6-O-[β-hydroxymyristoyl]-α-d-GlcNAc. VexE belongs to the lysophosphatidyl acyltransferase family, and comparison of an Alphafold VexE model to solved lysophosphatidyl acyltransferase structures, together with modeling enzyme:substrate complexes, led us to predict an enzyme mechanism. This study provides new insight into Vi terminal structure, offers a new model substrate to investigate the mechanism of glycolipid ABC transporters, and adds biochemical understanding for a novel reaction used in the synthesis of an important bacterial virulence factor.

Subcellular Fractionation for the Isolation of Synaptic Components from the Murine Brain.

Synaptic terminals are the primary sites of neuronal communication. Synaptic dysfunction is a hallmark of many neuropsychiatric and neurological disorders. The characterization of synaptic sub-compartments by biochemical isolation is, therefore, a powerful method to elucidate the molecular bases of synaptic processes, both in health and disease. This protocol describes the isolation of synaptic terminals and synaptic sub-compartments from mouse brains by subcellular fractionation. First, sealed synaptic terminal structures, known as synaptosomes, are isolated following brain tissue homogenization. Synaptosomes are neuronal pre- and post-synaptic compartments with pinched-off and sealed membranes. These structures retain a metabolically active state and are valuable for studying synaptic structure and function. The synaptosomes are then subjected to hypotonic lysis and ultracentrifugation to obtain synaptic sub-compartments enriched for synaptic vesicles, synaptic cytosol, and synaptic plasma membrane. Fraction purity is confirmed by electron microscopy and biochemical enrichment analysis for proteins specific to sub-synaptic compartments. The presented method is a straightforward and valuable tool for studying the structural and functional characteristics of the synapse and the molecular etiology of various brain disorders.

Comparison in radiation tolerance between FLR planar junction termination and positive bevel edge termination for power diodes

In this paper, a coupled electro-thermal simulation model is established to investigate the single event burnout (SEB)-induced failure in power diode. The radiation tolerance of the two different termination structures, the field limiting ring (FLR) planar junction termination and the positive bevel edge termination, is revealed comparatively. Firstly, through the comparison in the SEB threshold voltage, our simulation results indicate that the positive bevel edge termination exhibits a stronger robustness to SEB. The difference in the anti-radiation performance can even reach 29.02% under the same ion incidence condition. Then, to fully understand why there is such a large difference in the radiation tolerance, we observed the entire failure process and obtained the SEB mechanism for the two termination structures. For the FLR planar junction termination, the edge of the main junction is the most sensitive region to SEB, since the high electric field here caused by the junction curvature effect can easily lead to the strong carrier multiplication and a large localized current density. By contrast, for the positive bevel edge termination, the electric field can be effectively reduced along the beveled surface, therefore, there is no electric field crowding at the edge of the pn junction. As a result, the positive bevel edge termination naturally exhibits a superior anti-radiation performance compared to the FLR planar junction termination structure.

Methyltransferases of Riboviria.

Many viruses from the realm Riboviria infecting eukaryotic hosts encode protein domains with sequence similarity to S-adenosylmethionine-dependent methyltransferases. These protein domains are thought to be involved in methylation of the 5′-terminal cap structures in virus mRNAs. Some methyltransferase-like domains of Riboviria are homologous to the widespread cellular FtsJ/RrmJ-like methyltransferases involved in modification of cellular RNAs; other methyltransferases, found in a subset of positive-strand RNA viruses, have been assigned to a separate “Sindbis-like” family; and coronavirus-specific Nsp13/14-like methyltransferases appeared to be different from both those classes. The representative structures of proteins from all three groups belong to a specific variety of the Rossmann fold with a seven-stranded β-sheet, but it was unclear whether this structural similarity extends to the level of conserved sequence signatures. Here I survey methyltransferases in Riboviria and derive a joint sequence alignment model that covers all groups of virus methyltransferases and subsumes the previously defined conserved sequence motifs. Analysis of the spatial structures indicates that two highly conserved residues, a lysine and an aspartate, frequently contact a water molecule, which is located in the enzyme active center next to the methyl group of S-adenosylmethionine cofactor and could play a key role in the catalytic mechanism of the enzyme. Phylogenetic evidence indicates a likely origin of all methyltransferases of Riboviria from cellular RrmJ-like enzymes and their rapid divergence with infrequent horizontal transfer between distantly related viruses.

Numerical Study on Planning Inductive Charging Infrastructures for Electric Service Vehicles on Airport Aprons

Dynamic inductive charging is a contact-free technology to provide electric vehicles with energy while they are in motion, thus eliminating the need to conductively charge the batteries of those vehicles and, hence, the required vehicle downtimes. Airport aprons of commercial airports are potential systems to employ this charging technology to reduce aviation-induced CO2 emissions. To date, many vehicles operating on airport aprons are equipped with internal combustion engines burning diesel fuel, hence contributing to CO2 emissions and the global warming problem. However, airport aprons exhibit specific features that might make dynamic inductive charging technologies particularly interesting. It turns out that using this technology leads to some strategic infrastructure design questions for airport aprons about the spatial allocation of the required system components. In this paper, we experimentally analyze these design questions to explore under which conditions we can expect the resulting mathematical optimization problems to be relatively hard or easy to be solved, respectively, as well as the achievable solution quality. To this end, we report numerical results on a large-scale numerical study reflecting different types of spatial structures of terminals and airport aprons as they can be found at real-world airports.

NudC regulated Lis1 stability is essential for the maintenance of dynamic microtubule ends in axon terminals

SummaryIn the axon terminal, microtubule stability is decreased relative to the axon shaft. The dynamic microtubule plus ends found in the axon terminal have many functions, including serving as a docking site for the Cytoplasmic dynein motor. Here, we report an unexplored function of dynein in microtubule regulation in axon terminals: regulation of microtubule stability. Using a forward genetic screen, we identified a mutant with an abnormal axon terminal structure owing to a loss of function mutation in NudC. We show that, in the axon terminal, NudC is a chaperone for the protein Lis1. Decreased Lis1 in nudc axon terminals causes dynein/dynactin accumulation and increased microtubule stability. Microtubule dynamics can be restored by pharmacologically inhibiting dynein, implicating excess dynein motor function in microtubule stabilization. Together, our data support a model in which local NudC-Lis1 modulation of the dynein motor is critical for the regulation of microtubule stability in the axon terminal.

A new species of the snipe fly genus Rhagio Fabricius (Diptera: Rhagionidae) from Korea

A new species of the genus Rhagio Fabricius is described for the Korean peninsula, namely, R . seorsus sp. nov. We document the diagnosis, description, distribution data, and taxonomic remarks of this new snipe fly using external habitus and both male and female terminal structures. Additionally, a key to identifying the Korean Rhagio species is presented.

Ultra-Morphology and Mechanical Function of the Trichoideum Sensillum in Nabis rugosus (Linnaeus, 1758) (Insecta: Heteroptera: Cimicomorpha)

Simple SummaryNabis rugosus is a representative of the Nabidae family belonging to the heteropteran group. It is a predator of tiny insects and has different sensory receptors that detect environmental changes. The present study focuses on the antennal sensilla of N. rugosus, mainly on the trichoideum sensillum as mechanoreceptors for detecting various tactile factors surrounding the insect. The morphology of trichoideum mechanosensillum in N. rugosus was modelled as a three-dimensional structure from the derived data sets using SEM and TEM. Specific inner features of the sensillum are also presented, which will be useful to build a biosensor for detecting physical environmental parameters.The present study aims to investigate the morphological features of the antennal sensilla by using SEM and TEM. The construction of a 3D model of trichoideum sensillum using Amira software is presented in this paper. Five sensillum types, namely trichoideum, chaeticum, campaniformium, coeloconicum, and basiconicum, were recorded. This model exhibits the mechanosensillum components, including the embedded hair in a socket attached by the joint membrane and the dendrite connected to the hair base passing through the cuticle layers. TEM images present the dendrite way, micro-tubules inside the dendritic sheath, and terminal structure of the tubular dendrite body and so-called companion cells included in the receptor, e.g., tormogen and trichogen. The parameters noted for the external structure and ultrastructure of the mechano-receptor indicate that they are specific to a particular type of sensillum and would be useful in developing the model for a biosensor. Results show that bio-inspired sensors can be developed based on morphological and ultrastructural studies and to conduct mechanical studies on their components.

Simulation Aided Hardening of Power Diodes to Prevent Single Event Burnout

This article presents the coupled electrothermal simulation results of single event burnout (SEB) in power diode with field limiting rings termination structure. Two different hardening techniques of low carrier lifetime control and introducing the buffer layer are investigated comparatively in both the radiation tolerance improvement and the electrical performance degradation. Our simulations reveal that a significant reduction in the carrier lifetime is needed for the hardening of the power diode using only the carrier lifetime control method. However, the sharp increases in the forward voltage drop and the leakage current at the lower carrier lifetime make this hardening technique unacceptable. On the contrary, the addition of the buffer layer is able to improve the safe operating area under the heavy ion irradiation even up to the breakdown voltage, while the breakdown characteristics and the leakage current are kept unchanged and the increases in the forward voltage drop and the reverse recovery charge can be well controlled. In conclusion, adding a buffer layer is considered a superior and promising hardening technique.

A Simple Edge Termination Design for Vertical GaN P-N Diodes

Vertical power devices require significant attention to their edge termination designs to obtain higher breakdown voltages without substantial increase in ON-state resistance. A simple edge termination structure for a GaN p-n diode is proposed, comprising a full layer lightly doped p-type GaN region underneath the higher doped <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p} +\!+$ </tex-math></inline-formula> contact layer. A TCAD model of the device is developed, and removal of the portions of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula> ++ cap outside of the device active area in simulations is shown to increase the device blocking voltage capability. It causes the depletion width to increase in the lightly doped p-type layer and allows it to act similar to a junction termination extension (JTE). These predictions are validated empirically, resulting in a 52% measured increase in breakdown capability after selective removal of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula> ++ cap. This simple edge termination technique can be formed with only a single low-energy nitrogen implant or etching procedure, greatly increasing its manufacturability over more complex structures. Design optimization studies are pursued in TCAD to determine optimal parameter values for further improving breakdown performance. It is shown that the proposed edge termination technique can be employed to produce future high voltage vertical GaN devices without a significant gain in ON-state resistance and with wide tolerance to process variations.

Research on breakdown characteristics of 4H-SiC PIN avalanche diode in single-zone JTE terminal structure

Research on breakdown characteristics of 4H-SiC PIN avalanche diode in single-zone JTE terminal structure

Monolithic Integration of 1.2kV Optically-Controlled SiC npn Transistor and Antiparallel Diode

In this letter, a 1.2kV optically-controlled SiC transistor (OCT) is proposed and fabricated. A pin diode is monolithically integrated with the SiC OCT for reverse conducting and online junction temperature measurement capability. Field limiting rings are designed as terminal structure for forward blocking capability. The test results indicated that, besides full optical control and high blocking voltage performances, the fabricated transistor chip was also capable of reverse conducting and online junction temperature measurement. The forward breakdown voltage of the transistor was about 1400V and the leakage current at 1200V was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${2.5}\,\,\times \,\,{10}\,\,^{-{8}}\text{A}$ </tex-math></inline-formula> . The reverse turn-on voltage was about 2.6V, while the temperature sensitivity of the integrated diode was 2.99mV/K at 5mA. Under 365nm ultraviolet (UV) light with 300mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> incident intensity, the forward current of the OCT chip was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$203.2\mu \text{A}$ </tex-math></inline-formula> at 0.3V, which is about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${1.2}\,\,\times \,\,{10}\,\,^{{5}}$ </tex-math></inline-formula> times the corresponding dark current. The transient characteristic was tested at a 600V bias voltage in a resistive load circuit and the results indicate that the OCT can be switched using a 365nm UV light emitting diode.

Design of vertical diamond Schottky barrier diode with a novel beveled junction termination extension

In this paper, vertical diamond Schottky barrier diode with a beveled junction termination extension is designed by using Silvaco TCAD. We firstly investigate the effects of the pn junction termination extension on the electrical performances to optimize the doping concentration. In addition, the beveled structure with an angle of 45° decreases the current conduction path slightly, but it also enhances the reverse breakdown voltage effectively. By combining the junction termination extension and beveled structures, a new termination structure is proposed for the vertical diamond Schottky barrier diode. Under forward bias, the depletion region introduced by the pn junction hindrances the current conduction slightly and increases the on-resistance. However, the electric field crowding phenomenon is alleviated drastically under reverse bias, resulting in a more uniform electric field distribution and high breakdown voltage. Therefore, the beveled junction termination structure is promising to balance the on-resistance and the reverse breakdown voltage of the diamond Schottky barrier diode.

Failure mechanism of 4H-SiC junction barrier Schottky diodes under harsh thermal cycling stress

The concern in the long-term reliability of the SiC power devies is raised lately in power electronic field due to its brief history and limited data. In this work, discrete 1200 V/20A SiC JBS diodes have been intensively investigated by HTRB, HAST, and TCT. 2 % samples have failed in the harsh thermal cycling test, showing that the failure mechanism is attributed to field-oxide cracking. The electrical and physical failure analysis pointed out that a gradual degradation occurred at the termination structure, causing non-recoverable damages and provoking a significant increase in the leakage current. The FIB cut and SEM analysis showed the delamination existence between field oxide layer and silicon carbide layer in the degraded devices. The observed leakage current after the TCT could be well correlated with the formation of the delamination, which created a current leaking path between active and termination region. These findings emphasize the importance of SiO2/SiC interface quality in the long-term highly reliable SiC power devices, and indicate further optimized design of SiO2 passivation layer or other alternative materials is urgently needed to overcome this structural weakness.

Retinal Delivery of the Protein Kinase C-β Inhibitor Ruboxistaurin Using Non-Invasive Nanoparticles of Polyamidoamine Dendrimers.

Ruboxistaurin (RBX) is an anti-vascular endothelial growth factor (anti-VEGF) agent that is used in the treatment of diabetic retinopathy and is mainly given intravitreally. To provide a safe and effective method for RBX administration, this study was designed to develop RBX nanoparticles using polyamidoamine (PAMAM) dendrimer generation 5 for the treatment of diabetic retinopathy. Drug loading efficiency, and in vitro release of proposed complexes of RBX: PAMAM dendrimers were determined and the complexation ratio that showed the highest possible loading efficiency was selected. The drug loading efficiency (%) of 1:1, 2.5:1, and 5:1 complexes was 89.2%, 96.4%, and 97.6%, respectively. Loading capacities of 1:1, 2.5:1, and 5:1 complexes were 1.6%, 4.0%, and 7.2% respectively. In comparison, the 5:1 complex showed the best results in the aforementioned measurements. The in vitro release studies showed that in 8 h, the RBX release from 1:1, 2.5:1, and 5:1 complexes was 37.5%, 35.9%, and 77.0%, respectively. In particular, 5:1 complex showed the highest drug release. In addition, particle size measurements showed that the diameter of empty PAMAM dendrimers was 214.9 ± 8.5 nm, whereas the diameters of loaded PAMAM dendrimers in 1:1, 2.5:1, 5:1 complexes were found to be 461.0 ± 6.4, 482.4 ± 12.5, and 420.0 ± 7.1 nm, respectively. Polydispersity index (PDI) showed that there were no significant changes in the PDI between the free and loaded PAMAM dendrimers. The zeta potential measurements showed that the free and loaded nanoparticles possessed neutral charges due to the presence of anionic and cationic terminal structures. Furthermore, the safety of this formulation was apparent on the viability of the MIO-M1 cell lines. This nanoformulation will improve the therapeutic outcomes of anti-VEGF therapy and the bioavailability of RBX to prevent vision loss in patients with diabetic retinopathy.

(Invited) Breakdown Improvement and Reverse Recovery Characterization in Vertical GaN PN Diodes

Wide bandgap semiconductor devices based on gallium nitride (GaN) and silicon carbide (SiC) are attractive semiconductor technologies for future generation power electronics.Lateral GaN HEMTs have dominated the low voltage arena, while SiC MOSFETs have been the preferred technology for higher voltage applications. Devices based on GaN are regarded as having a strong potential for next generation power electronics owing to their high electron mobility, high thermal conductivity, high critical electric field and very low reverse recovery time. The theoretical high voltage capability of GaN is superior to both SiC and silicon (Si), which has resulted in significant government investment for the development of vertical GaN architectures, with a particular emphasis on thicker epitaxial layers, as well as more reliable substrates. The relative improvement in the development of native GaN substrates over the recent years has encouraged production of homo-epitaxial GaN-on-GaN vertical devices with low defect densities and reduced capacitances. Some major advantages of vertical GaN devices include their design robustness, due to avalanche breakdown capability, as well as their ability to attain higher blocking voltages through appropriate edge termination. One of the major challenges in designing junction terminations in GaN vertical devices is the limitation in selective area ptype doping. Selective area p-type doping in GaN is typically performed via Mg implantation, which is known to have a low activation efficiency as well as limited range of implant energy and dosage. Addressing these limitations requires innovative design of termination structures. Iterative refinement between TCAD modeling and fabrication can facilitate design optimization to improve breakdown potential. Circuit simulation can be used to project the performance of the device in various applications and benchmark its performance against other conventional materials.This paper proposes a vertical GaN diode with a blocking capability of 1.3 kV, acquired through a simple technique of edge termination. The initial device design consists of a very highly doped (2 × 1020 cm−3) p++ capping layer on top of the pGaN layer to facilitate the formation of a low resistance ohmic contact with the anode metal. Four samples differing in p-type doping levels are studied under reverse bias using Sentaurus TCAD (Synopsys). The simulations are used to examine the regions of the device that are highly susceptible to field crowding, leading to design considerations for improved breakdown performance. It is shown both through simulations and empirically, that elimination of the highly doped p++ capping layer allows the lower doped p-type layer to serve as a Junction Termination Extension (JTE). The proposed simplified technique of edge termination is produced by the regulation of charge in the lower doped pGaN layer, and does not require selective area p-type doping, thereby substantially improving the manufacturability. The empirically validated diode characteristics are then exported to a circuit simulator and compared to a similarly-rated commercially available Si ultra-fast diode using a double pulse test (DPT). Comparison of the switching characteristics of both the diodes reveals that the proposed GaN diode shows significantly higher efficiency during reverse recovery.Fig. 1 shows the shows the initial device design under consideration. A TCAD model of this device was then implemented in Sentaurus TCAD (Synopsys). The simulated device structure is shown in Fig. 2. Fig. 2(a) illustrates a magnified view of the drift and pGaN layer, above the substrate, while the mesh structure of the entire device is shown Fig. 2(b). Fig. 3 illustrates simulated and experimental static characteristics of the devices, both in terms of forward conduction, and reverse breakdown. As can be seen in Fig. 3, the model accurately predicts the static characteristics of the device. However, wafers two and three (W2 and W3) have significantly lower pGaN doping than wafer one and wafer four. This would suggest a greater breakdown voltage for wafer 2 and wafer 3. However, as seen in Fig. 3, this was not the case.Further analysis via TCAD reveals that the p++ capping layer is the reason for the premature breakdown of W2 and W3. Fig. 4 shows electric field distribution plots for W3 before and after selective removal of the p++ capping layer. Prior to removal, the electric field is unable to uniformly spread across the junction, as seen in Fig. 4(a). On the contrary, after removal of the p++ capping layer, a more uniform electric field distribution is obtained.These simulated results were validated experimentally as seen in Fig. 5. The p++ capping layer was etched away everywhere except underneath the anode. From Fig. 5, the breakdown potential of the device improves by approximately 50%. Figure 1

Computation of viscous flow characteristics of a supersonic intake using eddy-viscosity turbulence models

Results of numerical investigation of flow and performance characteristics of a rectangular supersonic intake experimentally tested at Mach number of 4.03 are presented. The viscous flowfield has been obtained by solving Favre averaged Navier–Stokes equations with two eddy viscosity turbulence models, namely, Mentor’s baseline (BSL) k-ω and shear stress transport (SST) k-ω models. In addition, the effect of wall temperature conditions as well as several configurations of cowl and isolator are simulated to validate the computational methodology. The analysis has been carried out at a freestream Mach number of 4.03 and 0° angle-of-attack, corresponding to a unit Reynolds number of about 6.9×107 m−1. The predicted boundary-layer and the wall static pressure distribution using SST k-ω model shows better agreement with the experimental data compared to the BSL model and hence indicates superior capability to capture the onset and the amount of flow separation due to SWBLIs. Moreover, the terminal shock structure at different operating modes as well as the “unstart because of SWBLIs” is predicted quite accurately using the model. The wall temperature condition is found to have a strong effect on the amount of flow separation at the cowl and the subsequent interactions. Further, the results show that the sidewalls have a marginal effect on the centerline wall static pressure, though a three-dimensional flowfield with two stream-wise vortices are observed close to it as a result of the swept SWBLIs of the cowl shock with the sidewall boundary-layer leading to a higher loss in performance.

Design of vertical diamond Schottky barrier diode with junction terminal extension structure by using the n-Ga2O3/p-diamond heterojunction

A novel junction terminal extension structure is proposed for vertical diamond Schottky barrier diodes (SBDs) by using an n-Ga2O3/p-diamond heterojunction. The depletion region of the heterojunction suppresses part of the forward current conduction path, which slightly increases the on-resistance. On the other hand, the reverse breakdown voltage is enhanced obviously because of attenuated electric field crowding. By optimizing the doping concentration, length, and depth of n-Ga2O3, the trade-off between on-resistance and breakdown voltage with a high Baliga figure of merit (FOM) value is realized through Silvaco technology computer-aided design simulation. In addition, the effect of the work functions of the Schottky electrodes is evaluated. The results are beneficial to realizing a high-performance vertical diamond SBD.