Agnitron Technology (United States)

See the retraction notice EPJ Web of Conferences 359 , 00002 (2026), https://doi.org/10.1051/epjconf/202635900002

β-Ga2O3 has become increasingly important in power electronics due to its wide bandgap (~4.9 eV) and high breakdown field (~8 MV/cm). Metalorganic chemical vapor deposition (MOCVD) is particularly effective for growing high-purity, low-dislocation β-Ga2O3 films with excellent low-temperature electron mobility (10,000–23,000 cm²/Vs) and minimal impurities [1-4]. However, traditional MOCVD showerhead designs limit growth rates, doping precision, and surface smoothness on large substrates. Agnitron Technology has addressed these challenges with an innovative showerhead design that significantly improves film quality and uniformity. This presentation will discuss the successful development of extremely smooth (<1 nm) and uniform β-Ga2O3 films on larger area substrates using this new showerhead technology. Films with thickness and doping uniformity below 2.5% were achieved on 50 mm substrates at approximately 20 µm/hr growth rates. The electrical mobility values were independent of the growth rate, remaining constant (~91 cm²/Vs with an electron concentration of n=5x10¹⁷ cm⁻³) across growth rates ranging from 1.7 µm/hr to 13 µm/hr. This demonstrates the potential of this technology to a

We report on the demonstration of β-Ga2O3 MOSFETs fabricated on 1-in. bulk substrates using metalorganic vapor phase epitaxy (MOVPE) with disilane (Si2H6) as the silicon precursor. Sheet charge uniformity of the as-grown films was measured via Hall and ranged from 5.9–6.7 × 1012 cm−2 with a uniform Hall mobility of 125–129 cm2/V s across the sample. MOSFET devices with a source-drain length of 5.1 μm were measured across the wafer and had a minimum on-resistance (RON) of 47.87 Ω mm with a maximum on-current (ION) of 165 mA/mm. For these same devices, the on-current (ION) and pinch-off voltage (VP) uniformity across the wafer were 137 ± 12 mA/mm and −27.3 ± 7.3 V, respectively. Devices showed low reverse leakage current until catastrophic breakdown occurred, with measured breakdown voltages (VBR) of up to 2.15 kV. This work provides valuable insights into understanding the growth, fabrication, and characterization processes for β-Ga2O3 FETs on full wafer-scale substrates. It also projects the promise of developing lateral β-Ga2O3 FETs with high current-carrying capabilities and breakdown voltages, especially on substrates of 1 in. or larger.

There is significant recent interest in development of Ga2O3 power devices due to their capability for high temperature operation, reduced on-state and switching losses due to lower on-resistance for high voltage devices, and potentially higher frequency switching capability. These are targeted for renewable energy transmission systems, electric vehicle (EV) traction inverter and motor control systems, fast charging stations and more electric aircraft. Since the efficiency of EV powertrain inverters is partially determined by the efficiency of the switching transistors, it is of interest to examine ultra-wide-bandgap semiconductor electronics. The successful development of these power transistors is expected to significantly increase the longevity of a battery charge and the resultant cost of an EV.In this work, NiO/ β-(Al x Ga1-x )2O3 /Ga2O3 heterojunction lateral geometry rectifiers with diameter 50-100 µm exhibited maximum reverse breakdown voltages >7kV, showing the advantage of increasing the bandgap using the β-(Al x Ga1-x )2O3 alloy. This Si-doped alloy layer was grown by Metal Organic Chemical Vapor Deposition with an Al composition of ~20%. On state resistances were in the range 50-2180 Ω.cm2, leading to power figures-of-merit up to 0.72 MW.cm-2. The forward turn-on voltage was in the range 2.3-2.5 V, with maximum on/off ratios >700 when switching from 5V forward to reverse biases up to -100V. Transmission line measurements showed the specific contact resistance was 0.12 Ω.cm2. The breakdown voltage is among the highest reported for any lateral geometry Ga2O3-based device. Figure 1

NiO/β-(AlxGa1−x)2O3/Ga2O3 heterojunction lateral geometry rectifiers with diameter 50–100 μm exhibited maximum reverse breakdown voltages &amp;gt;7 kV, showing the advantage of increasing the bandgap using the β-(AlxGa1−x)2O3 alloy. This Si-doped alloy layer was grown by metal organic chemical vapor deposition with an Al composition of ∼21%. On-state resistances were in the range of 50–2180 Ω cm2, leading to power figures-of-merit up to 0.72 MW cm−2. The forward turn-on voltage was in the range of 2.3–2.5 V, with maximum on/off ratios &amp;gt;700 when switching from 5 V forward to reverse biases up to −100 V. Transmission line measurements showed the specific contact resistance was 0.12 Ω cm2. The breakdown voltage is among the highest reported for any lateral geometry Ga2O3-based rectifier.

The band offsets for the β-(Al0.21Ga0.79)2O3/β-Ga2O3 (010) heterojunction have been experimentally measured by X-ray photoelectron spectroscopy. High-quality β-(Al0.21Ga0.79)2O3 films were grown by metal-organic chemical vapor deposition for characterization. The indirect band gap of β-(Al0.21Ga0.79)2O3 was determined by optical transmission to be 4.69 ± 0.03 eV with a direct transition of 5.37 ± 0.03 eV, while β-Ga2O3 was confirmed to have an indirect band gap of 4.52 ± 0.03 eV with a direct transition of 4.94 ± 0.03 eV. The resulting band alignment at the heterojunction was determined to be of type II with the valence and conduction band edges of β-(Al0.21Ga0.79)2O3 being -0.26 ± 0.08 and 0.43 ± 0.08 eV, respectively, above those of β-Ga2O3 (010). These values can now be used to help better design and predict the performance of β-(AlxGa1-x)2O3 heterojunction-based devices.

Abstract The reliability of the digital forensic system mainly lies in its ability to detect the attack on time and minimize the security risk associated with the Internet of Things (IoT) device. The existing machine learning architectures mainly suffered from different complexities while processing the attack features such as increased processing time, high manual intervention, complexity to handle large datasets, and low prediction accuracy. To overcome these issues, this article proposes a novel deep learning architecture for data forensics. The low generalization capability of the neural network is handled via the Hadoop clustering and convolution‐based ADAM (CADAM) optimizer approach for improving the optimization capability of the model. In this way, the privacy of the model is improved. The efficiency of the proposed CADAM optimized deep neural network architecture is evaluated by using the UNSW‐NB15 and Bot‐IoT datasets. The proposed model offers improved performance in terms of runtime, precision, sensitivity, specificity, latency, cost, ROCAUC curve, and anomalous traffic when compared with the existing techniques. From the experiments carried out, we can conclude that the proposed framework revealed higher performance to discover and prevent cyber‐attacks against other conventional approaches.

We report on the Ge doping of Ga2O3 using metalorganic chemical vapor deposition (MOCVD) epitaxy. The effects of the GeH4/N2 flow rate, substrate temperature, VI/III ratio, type of Ga precursor, and MOCVD reactor geometry on the incorporation efficiency of Ge into Ga2O3 were explored. The Ge concentration incorporated into the films was quantified using Hall and secondary ion mass spectroscopy measurements. The increase in the GeH4/N2 flow rate, decrease in the substrate temperature, and increase in the VI/III ratio increase the amount of Ge incorporated into Ga2O3. The incorporation of Ge into the lattice of Ga2O3 was found to be strongly dependent on the substrate temperature, i.e., lowering the growth temperature leads to a higher doping concentration. Films with a free carrier concentration ranging from ∼2 × 1016 to ∼3 × 1020 cm−3 and corresponding mobilities ranging from ∼140 to ∼38 cm2/Vs were realized. The incorporation of Ge into the films was also found to be strongly dependent on the metalorganic precursor type used for the growth of the Ga2O3 film. We found that it was more challenging to dope Ga2O3 with Ge using trimethylgallium rather than triethylgallium as a source for Ga. Additionally, we found that Ge doping has a strong memory effect dependent on the reactor geometry. The result highlights the challenges in achieving controllable Ge doping for n-type conductivity despite all the positive indicators from theoretical studies that suggest that Ge is a suitable dopant candidate for Ga2O3 similar to Si and Sn.

We report on the growth of β-Ga2O3 thin films using trimethylgallium (TMGa) as a source for gallium and pure O2 for oxidation. The growth rate of the films was found to linearly increase with the increase in the molar flow rate of TMGa and reach as high as ∼6 μm/h at a flow rate of 580 μmol/min. High purity, lightly Si-doped homoepitaxial β-Ga2O3 films with a good surface morphology, a record low temperature electron mobility exceeding 23 000 cm2/V s at 32 K, and an acceptor concentration of 2 × 1013 cm−3 were realized, showing an excellent purity film. Films with room temperature (RT) electron mobilities ranging from 71 cm2/V s to 138 cm2/V s with the corresponding free carrier densities between ∼1.1 × 1019 cm−3 and ∼1.5 × 1016 were demonstrated. For layers with the doping concentration in the range of high-1017 and low-1018 cm−3, the RT electron mobility values were consistently more than 100 cm2/V s, suggesting that TMGa is suitable to grow channel layers for lateral devices, such as field effect transistors. The results demonstrate excellent purity of the films produced and confirm the suitability of the TMGa precursor for the growth of device quality β-Ga2O3 films at a fast growth rate, meeting the demands for commercializing Ga2O3-based high voltage power devices by metalorganic chemical vapor deposition.

This chapter is devoted to the growth of Ga2O3 and its alloys by metalorganic chemical vapor deposition (MOCVD) or, equivalently, metalorganic vapor phase epitaxy (MOVPE). MOCVD is a standard epitaxial growth technique used for nitride, III–V, and oxide-based power devices as well as LEDs and laser diodes. It would, therefore, seem that MOCVD would be the most appropriate growth method to accelerate the development and commercialization of Ga2O3. However, molecular beam epitaxy (MBE) and halide vapor phase epitaxy (HVPE) were commonly used in the earlier growth studies of Ga2O3 epitaxial films. Fortunately, the broad range of knowledge available on the hardware and control systems of the MOCVD tool for the growth of device quality epitaxial films makes it easily adaptable to the growth of epitaxial Ga2O3. Device quality films grown at ~10 µm/h were demonstrated [1, 2], evidencing the ability of MOCVD to achieve the high throughput Ga2O3 epitaxial layer growth needed for high voltage power device and deep ultraviolet solar-blind photodetector commercial applications. This chapter discusses the following topics: the selection of suitable metalorganic precursors and oxygen sources used for the growth of Ga2O3 and (Al, Ga)2O3 alloys; the need for the careful design of the MOCVD reactors, homoepitaxial and heteroepitaxial growth on c-plane sapphire and native Ga2O3 substrates, donor and acceptor doping; and the origin and methods for mitigating or reducing unintentional impurities.