Regrowth Technique Research Articles

Improvement of electrical performance in Normally-Off GaN MOSFET with regrown AlGaN layer on the Source/Drain region

A normally-off GaN MOSFET is successfully fabricated by using the selective regrowth technique (SRT) with regrown AlGaN layer on source/drain (S/D) region. The GaN MOSFET with regrown AlGaN layer and Lg of 10 μm shows enhanced electrical performance such as maximum drain current (ID,max) of 57 mA/mm, maximum transconductance (gm,max) of 11 mS/mm, and field-effect mobility (μFE) of 59 cm2/V·s, respectively, compared to the GaN MOSFET with n+-GaN selective regrowth in S/D region. This is because of the high 2DEG density formed by AlGaN/GaN heterojunction in S/D region. Moreover, to accommodate the poor structural quality of the narrow region regrowth of AlGaN layer on the S/D region, wide regrown AlGaN layer is applied to the GaN MOSFET. Especially, the off-state breakdown voltage improves from 25 V to 192 V with the improved structural quality of wide regrown AlGaN layer and optimized structure and the application of the 70-nm thick SiO2 passivation. These result shows that GaN MOSFET with wide regrown AlGaN layer on S/D region is beneficial to achieving high-quality and uniform normally-off GaN MOSFETs with excellent electrical performance.

Monolithically integrated four-channel laser array based on high-order surface gratings for O-band CWDM systems

An O-band monolithically integrated four-channel laser array based on high-order surface gratings is demonstrated. The fabricated laser array exhibits a wide bandwidth of up to 60 nm, with threshold currents ranging from 17 to 25 mA and slope efficiencies between 0.22 and 0.29 W/A. At an injection current of 200 mA, all side-mode suppression ratios (SMSRs) are above 40 dB, and the output power exceeds 36 mW. The high-order surface gratings are fabricated by standard lithography, which avoids high-precision lithography and a complex regrowth technique. A potentially cost-effective light source for coarse wavelength division multiplexing (CWDM) systems is provided.

Effect of Ultra‐Thin AlGaN Regrown Layer on the Electrical Properties of ZrO2/AlGaN/GaN Structures

Effects of the ultrathin 1 nm thick AlGaN regrown layer before gate insulator deposition on the performance of ZrO2/AlGaN/GaN metal‐insulator‐semiconductor (MIS) structures are investigated. In comparison with the reference ZrO2/AlGaN/GaN MIS high‐electron‐mobility transistors (MIS‐HEMTs), MIS‐HEMTs with AlGaN regrown layer exhibit increased maximum drain current (>1050 mA mm−1) and broader full‐width at half maximum (FWHM) of transconductance profile (11 V). Moreover, the gate leakage current in the forward direction is reduced by about four orders of magnitude while the hysteresis of the transfer curves is cut‐down to more than 40%. Compared with the control MIS‐capacitors (MIS‐caps), MIS‐caps with regrowth show highly evident sudden increase in capacitance known as “spill‐over” in the capacitance–voltage (C–V) profiles, suggesting improved ZrO2/AlGaN interfaces. Extracted electron states from the C–V profiles, reveal 6 times to 14 times reduction of interface states density within 0.2 to 0.8 eV from the AlGaN conduction band edge. Using photo‐assisted C–V measurements, the near mid‐gap electron states density of MIS‐caps is extracted with regrowth to be at least three times less than those of reference MIS‐caps. Findings in this work are very similar to those recently reported Al2O3/regrown‐AlGaN interfaces, suggesting that the regrowth technique could be universal in reducing electron states along insulator/AlGaN interfaces.

Fabrication of Low On‐Resistance and Normally Off AlGaN/GaN Metal Oxide Semiconductor Heterojunction Field‐Effect Transistors with AlGaN Back Barrier by the Selective Area Regrowth Technique

Herein, a recessed‐gate AlGaN/GaN metal oxide semiconductor heterojunction field‐effect transistor (MOS‐HFET) with an AlGaN back‐barrier layer fabricated by a selective area regrowth (SAG) technique is investigated. A recessed‐gate structure enables normally off operation required for power‐switching applications. A thin AlGaN/GaN channel and the AlGaN back‐barrier structures are fabricated on a Si substrate by metal–organic chemical vapor deposition. The 50 nm thick, thin GaN channel layer with a smooth surface is grown on the AlGaN back‐barrier layer. A recessed‐gate structure is successfully formed by SAG of an AlGaN/GaN layer on the thin AlGaN/GaN layer. The regrown AlGaN/GaN high electron mobility transistor structure shows lower sheet resistance owing to high concentration and high mobility of a two‐dimensional electron gas. Transfer characteristics of the thin AlGaN/GaN channel MOS‐HFETs show normally off operation as a consequence of using the AlGaN back‐barrier structure. Channel mobility becomes five times higher than that of GaN channel in the case of using the thin AlGaN/GaN channel. These results indicate that the regrown thin AlGaN/GaN channel MOS‐HFET has the potential to realize low on‐resistance and normally off operation.

Realization of all-crystalline GaN/Er:GaN/GaN core-cladding optical fiber structures

Erbium-doped gallium nitride (Er:GaN) is a promising gain material for solid-state high-energy lasers operating in the 1.5 μm wavelength window due to the superior optical properties and extremely high thermal conductivity of a GaN host crystal that permit high-power and high-temperature applications. We report the realization of all-crystalline GaN/Er:GaN/GaN embedded waveguide fiber structures using the hydride vapor phase epitaxy growth and re-growth technique, along with chemical–mechanical polishing processes. The Er:GaN core layer possesses an Er doping concentration of 1.7×1020 atoms/cm3, confirmed by secondary ion mass spectrometry measurements. X-ray diffraction measurements confirm, respectively, c-, a-, and m-plane orientations for top/bottom, side, and front/back cross-sectional cladding layers of the fiber structure with good single-crystalline quality. The 1.5 μm Er3+ emission was detected from each surface of the fiber structures via 980 nm resonant excitation. The effect of 1.54 μm light guiding by the fiber structure has been demonstrated. This work laid the foundation toward achieving all-crystalline core-cladding fibers based on GaN wide bandgap semiconductor with potential applications in the harsh environments of high powers, power densities, and temperatures.

Low-Resistance Ta/Al/Ni/Au Ohmic Contact and Formation Mechanism on AlN/GaN HEMT

In this article, we systematically investigated the Ta/Al/Ni/Au and Ti/Al/Ni/Au ohmic contacts, and contact formation mechanism on ultrawide bandgap (UWBG) AlN barrier heterostructure without using the source–drain regrowth technique. The excellent ohmic contact performance of the Ta-based scheme was observed. The transmission line model (TLM) results depicted an ultralow contact resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.08 \Omega \cdot $ </tex-math></inline-formula> mm and a specific contact resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.06\times 10^{-{7}} \,\, \Omega \cdot $ </tex-math></inline-formula> cm2. Atomic force microscope (AFM) shows that the Ta/Al/Ni/Au sample presents a surface morphology improvement compared with the Ti/Al/Ni/Au sample. Transmission electron microscope (TEM) illustrated that the dominant contact mechanism for ultralow resistance is direct contact through TaxAlyAuz alloy penetration. Meanwhile, the difficulty of contact formation for the Ti-based sample was also discussed through the microstructural analysis. These results demonstrate that the proposed Ta/Al/Ni/Au metal scheme is a high-performance and cost-effective ohmic contact technique well suited for AlN/GaN HEMT fabrication process.

Dislocation Formation and Filtering in III–V Regrowth on GaAs Bonded on Si

We develop a process to regrow thick III-As layers on a thin bonded template of GaAs on Si and uncover how to control the formation of threading dislocations. Such a hybrid approach potentially combines the advantages of full device wafer bonding and direct epitaxial growth for III–V optoelectronic integration on Si. One lingering challenge to this postbond regrowth technique, however, is thermal expansion mismatch between the film and substrate, leading to high dislocation densities when growing beyond the critical thickness. We find that the threading dislocation density of a simple 2.2 μm GaAs regrowth film rises as high as 8 × 106 cm–2, orders of magnitude higher than the original template density. Using compressively strained dislocation blocking layers, threading dislocation densities are reduced by as much as 30× down to 2.7 × 105 cm–2, and it is shown that, unexpectedly, most dislocations nucleate during cooldown following growth when the strain state reverses from compressive to tensile because of thermal expansion mismatch. Finally, potential design modifications are proposed to improve dislocation filtering efficacy and for growing device structures.

Low-resistance ohmic contacts on InAlN/GaN heterostructures with MOCVD-regrown n+-InGaN and mask-free regrowth process

This paper studied the low-resistance ohmic contacts on InAlN/GaN with metal--organic chemical vapor deposition (MOCVD) regrowth technique. The 150-nm regrown n+-InGaN exhibits a low sheet resistance of 31 Ω/□, resulting in an extremely low contact resistance of 0.102 Ω⋅mm between n+-InGaN and InAlN/GaN channels. Mask-free regrowth process was also used to significantly improve the sheet resistance of InAlN/GaN with MOCVD regrown ohmic contacts. Then, the diffusion mechanism between n+-InGaN and InAlN during regrowth process was investigated with electrical and structural characterizations, which could benefit the further process optimization.

Two-dimensional polarization doping of GaN heterojunction and its potential for realizing lateral p–n junction devices

In the gallium nitride (GaN) commercial applications such as high-power illumination and portable charging station, bipolar devices are highly demanded because of their superior power transfer capability. Also, in other scenarios of the monolithic integration where high electron mobility transistors (HEMTs) or superlattice-based devices are presented, the peripheral components are preferred to be lateral. However, to realize such a lateral bipolar junction in GaN, high-concentration p-type dopant doping is still challenging and hardly compatible with the HEMT integration. In this work, we proposed a novel strategy to form lateral bipolar GaN p–n junctions, enabled by the two-dimensional polarization doping. The theory and the simulation reveal this strategy features inspiring forwarding, blocking, and switching performance. Given the recent success of the GaN selective area regrowth techniques, the proposed lateral bipolar junction is highly promising in monolithic heterojunction integration in the future.

Normally-OFF AlGaN/GaN MIS-HEMTs With Low RON and Vth Hysteresis by Functioning In-situ SiNx in Regrowth Process

Normally-off AlGaN/GaN MIS-HEMTs with a high threshold voltage (<inline-formula> <tex-math notation="LaTeX">$\text{V}_{\text {th}}$ </tex-math></inline-formula>) more than 2.5 V and a low on- resistance of <inline-formula> <tex-math notation="LaTeX">$5.5\Omega \cdot $ </tex-math></inline-formula>mm have been achieved by an improved regrowth technique with <i>in-situ</i> SiN_<i>x</i> passivation. A thin-barrier heterojunction was used to decrease the two-dimensional electron gas (2DEG) underneath the gate, then regrown Al_0.2Ga_0.8N and <i>in-situ</i> SiN_<i>x</i> were applied to recover 2DEG at the access regions and reduce contact resistance. The O₃-based Al₂O₃ and HfO₂ were employed to cover the recessed-gate with low channel sheet resistances by atomic layer deposition. The other hybrid MIS-HEMT with <i>in-situ</i> SiN_<i>x</i> gate interlayer also enabled a normally-off operation with a <inline-formula> <tex-math notation="LaTeX">$\text{V}_{\text {th}}$ </tex-math></inline-formula> hysteresis lower than 30 mV. The damage-free recessed-gate structures with in- situ SiN_<i>x</i> as passivation and gate dielectric contribute to reducing surface scattering and interface states, resulting in a high <inline-formula> <tex-math notation="LaTeX">$\text{V}_{\text {th}}$ </tex-math></inline-formula> uniformity and channel mobility, low on- resistance and_th hysteresis in normally-off GaN-based MIS-HEMTs.

Self-Assembly and Regrowth of Metal Halide Perovskite Nanocrystals for Optoelectronic Applications.

ConspectusOver the past decade, the impressive development of metal halide perovskites (MHPs) has made them leading candidates for applications in photovoltaics (PVs), X-ray scintillators, and light-emitting diodes (LEDs). Constructing MHP nanocrystals (NCs) with promising optoelectronic properties using a low-cost approach is critical to realizing their commercial potential. Self-assembly and regrowth techniques provide a simple and powerful “bottom-up” platform for controlling the structure, shape, and dimensionality of MHP NCs. The soft ionic nature of MHP NCs, in conjunction with their low formation energy, rapid anion exchange, and ease of ion migration, enables the rearrangement of their overall appearance via self-assembly or regrowth. Because of their low formation energy and highly dynamic surface ligands, MHP NCs have a higher propensity to regrow than conventional hard-lattice NCs. Moreover, their self-assembly and regrowth can be achieved simultaneously. The self-assembly of NCs into close-packed, long-range-ordered mesostructures provides a platform for modulating their electronic properties (e.g., conductivity and carrier mobility). Moreover, assembled MHP NCs exhibit collective properties (e.g., superfluorescence, renormalized emission, longer phase coherence times, and long exciton diffusion lengths) that can translate into dramatic improvements in device performance. Further regrowth into fused MHP nanostructures with the removal of ligand barriers between NCs could facilitate charge carrier transport, eliminate surface point defects, and enhance stability against moisture, light, and electron-beam irradiation. However, the synthesis strategies, diversity and complexity of structures, and optoelectronic applications that emanate from the self-assembly and regrowth of MHPs have not yet received much attention. Consequently, a comprehensive understanding of the design principles of self-assembled and fused MHP nanostructures will fuel further advances in their optoelectronic applications.In this Account, we review the latest developments in the self-assembly and regrowth of MHP NCs. We begin with a survey of the mechanisms, driving forces, and techniques for controlling MHP NC self-assembly. We then explore the phase transition of fused MHP nanostructures at the atomic level, delving into the mechanisms of facet-directed connections and the kinetics of their shape-modulation behavior, which have been elucidated with the aid of high-resolution transmission electron microscopy (HRTEM) and first-principles density functional theory calculations of surface energies. We further outline the applications of assembled and fused nanostructures. Finally, we conclude with a perspective on current challenges and future directions in the field of MHP NCs.

Heterogeneously integrated membrane III-V compound semiconductor devices with silicon photonics platform

Silicon photonics is a key technology for constructing large-scale photonic integrated circuits (PICs) because it enables large-scale wafer processes with high uniformity and quality. To further improve device characteristics, heterogeneous integration of III-V compound semiconductors that provide optical gain, a high modulation efficiency, and optical non-linearity is desired. This paper describes the heterogeneous integration of membrane III-V compound semiconductor photonic devices that have a similar structure including thickness and refractive index. These devices provide efficient optical coupling with a Si waveguide using a simple taper waveguide structure. If the total thickness of the film structure is designed to be less than the critical thickness (calculated to be 430 nm for fabrication conditions such as bonding and growth temperatures), high-quality epitaxial layers can be grown on a thin InP layer directly bonded to the Si substrate. Therefore, regrowth techniques are employed on bonded InP layer on SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si substrate. We fabricate two kinds of laser-integrated Mach-Zehnder modulators using epitaxial regrowth on Si substrates. One uses Si phase modulators, and the other uses InP-based modulators. A micro-transfer-printing technology is also important when the number of III-V devices is relatively small. Furthermore, the micro-transfer-printing technology enables devices to be selected that meet the required characteristics before integration. For this purpose, we try to integrate a membrane laser on a Si substrate, in which the membrane laser is fabricated on InP substrate. The device shows a threshold current of 0.8 mA when the active region length is 140 μm. Finally, we briefly describe a transmission module, in which directly modulated membrane lasers and electronic drivers are integrated by flip-chip bonding through Au bumps. To reduce power consumption, it is important to design driver circuits that incorporate semiconductor lasers as electronic components. We demonstrate a 2-channel 53-Gbit/s 4-level pulse amplitude modulation (PAM4) transmitter front-end consisting of a 2-channel PAM4 shunt laser driver and 2-channel O-band directly modulated membrane lasers. The total power consumption is only 60.7 mW, resulting in 0.57 mW/Gbit/s.

Quantitative phase analysis of Bi2Sr2CaCu2O8+x and competing intergrowth and co-crystallizing phases via a Rietveld refinement study

The Rietveld refinement technique has been used to determine the extent of intergrowth of the Bi2Sr2CuO6+x phase and co-crystallization of competing phases in the high-temperature superconductor Bi2Sr2CaCu2O8+x (Bi-2212). The refinement was done on powder diffractograms obtained on powders made by grinding single crystals of Bi2Sr2CaCu2O8+x grown using two different self-flux techniques, namely the pressure technique and the regrowth technique, and ground for either 2 min or 2 h. The Rietveld programs JANA and FULLPROF were used for the refinement and both gave consistent results. The Bi and Sr atom positions were refined in the average structure of centrosymmetric space group Bbmb. To incorporate Bi-atom modulation and extract information about the modulation vector, refinement was done in the centrosymmetric space group N^{Bbmb}_{1\overline 11}(Bbmb(0γ1)). The b* component of the modulation vector decreases with a decrease in the superconducting transition temperature in the pressure-technique sample compared with the regrowth sample, suggesting a better alignment of the CuO2 planes with respect to the Bi–O planes in the pressure-technique sample. All the samples exhibit a strong preferred orientation effect. Values of the March–Dollase parameters corresponding to the preferred orientation function were obtained. Brindley absorption contrast factors t ϕ were also calculated, together with the effect of microabsorption on the number of phases present in each sample. Rietveld refinements incorporating all the factors resulted in excellent values for the goodness-of-fit parameters for all the samples, with the lowest value of 2.08 for the pressure-technique sample ground for 2 min. Additionally, the powders corresponding to the pressure-technique crystals have no co-crystallizing phase and ∼94% of the Bi-2212 phase, suggesting that crystals grown by the pressure technique are of extremely good quality, much better than those grown by the regrowth flux technique.

Global warming allows two grape crops a year, with about two months apart in ripening dates and with very different grape composition - The forcing vine regrowth to obtain two crops a year

With the aim of delaying the ripening of grapes by around two months, a technique has been proposed based on forcing vine regrowth (Gu et al. 2012, Martinez de Toda et al. 2019). It is a bold method to fight against climate warming that could be only developed in really warm viticultural regions. It consists in shortening the growing shoots to several nodes with the aim of forcing vine regrowth; in order to force budbreak, shoot regrowth, and cropping, the source of inhibition needs to be eliminated and to this end, lateral shoots, leaves, and primary clusters, if they exist, are removed.But the main drawback of the forcing vine regrowth technique is loss of yield. In order to avoid this loss of yield and not to eliminate the primary clusters already formed in the main shoots, it is possible to force the development of buds of the fifth and sixth nodes, but maintaining the clusters of the main shoots. In this way, the yield of the forced buds would be added to the normal or primary yield of the shoots. The experiences carried out with 'Grenache', 'Tempranillo' and 'Maturana Tinta' varieties in La Rioja (Spain) are presented.

Floristic composition and above-ground net primary production in natural grasslands on basaltic deep soils

In natural grasslands of the basaltic region, livestock management is applied traditionally associated with continuous high stocking density resulting in the degradation of natural grasslands. Traditionally, aboveground net primary production (ANPP) was estimated from biomass cuts made in the fields. Today, it is possible to estimate ANPP using remote sensing techniques by synthetic images of enhanced vegetation index (EVI). Considering these, we aimed this study to: a) determine the effect of contrasting grazing managements on floristic composition, b) estimate the radiation use efficiency coefficient (RUE) and its seasonal variation, and c) determine the ANPP for two contrasting grazing methods. The experiment was carried out in five farms in the basaltic region of Uruguay with mixed grazing under natural grasslands from spring 2013 to summer 2015. Paddocks with contrasting livestock management were chosen in each site. Vegetation growth was measured using the re-growth technique with three exclusion cages. Floristic composition was estimated using the Braun Blanquet scale. RUE coefficient was estimated following the equation: ANPP = APAR×RUE, where APAR is the absorbed photosynthetically active radiation. Changes in the floristic composition, ANPP, and RUE coefficient were recorded throughout the study in the two treatments. The RUE data obtained will be used to estimate ANPP in natural grasslands more accurately.

Grapevine double cropping: a reality, not a myth

The main drawback of the forcing vine regrowth technique is the loss of yield (Martínez de Toda, 2020). In order to avoid such loss of yield and not eliminate the primary clusters already formed on the primary shoots, it is possible to force the development of the latent buds of the fifth and sixth nodes, while maintaining the clusters on the main shoots. In this way, the yield of the forced buds can be added to the normal or primary yield of the shoots. In this article, experiments carried out on Grenache, Tempranillo and Maturana Tinta varieties in La Rioja (Spain) are presented.

High Threshold Voltage Normally off Ultra-Thin-Barrier GaN MISHEMT with MOCVD-Regrown Ohmics and Si-Rich LPCVD-SiNx Gate Insulator

A high threshold voltage (VTH) normally off GaN MISHEMTs with a uniform threshold voltage distribution (VTH = 4.25 ± 0.1 V at IDS = 1 μA/mm) were demonstrated by the selective area ohmic regrowth technique together with an Si-rich LPCVD-SiNx gate insulator. In the conventional GaN MOSFET structure, the carriers were induced by the inversion channel at a high positive gate voltage. However, this design sacrifices the channel mobility and reliability because a huge number of carriers are beneath the gate insulator directly during operation. In this study, a 3-nm ultra-thin Al0.25Ga0.75N barrier was adopted to provide a two-dimensional electron gas (2DEG) channel underneath the gate terminal and selective area MOCVD-regrowth layer to improve the ohmic contact resistivity. An Si-rich LPCVD-SiNx gate insulator was employed to absorb trace oxygen contamination on the GaN surface and to improve the insulator/GaN interface quality. Based on the breakdown voltage, current density, and dynamic RON measured results, the proposed LPCVD-MISHEMT provides a potential candidate solution for switching power electronics.

Low-Temperature Ohmic Contacts to n-ZnSe for all-Electrical Quantum Devices

The II/VI semiconductor ZnSe is an ideal host for novel devices for quantum computation and communication as it can be made nuclear-spin free to obtain long electron spin coherence times, exhibits no electron valley-degeneracy, and allows optical access. A prerequisite to electrical quantum devices is low-resistive Ohmic contacts operating at temperatures below 10 K, which have not been achieved in ZnSe yet. Here, we present a comprehensive study on the realization of Ohmic contacts to ZnSe by three different technological approaches, ion implantation of halogen donors, epitaxial doping with in situ contact processing, and finally, a unique ZnSe regrowth technique. The latter allows fabrication of Ohmic contacts with local doping that can be used to connect to a buried conducting channel such as those used in unipolar devices. DC measurements revealed high contact resistivity for Ohmic contacts to ZnSe doped via halogene ion implantation, while in situ aluminum (Al) contacts on epitaxially chlorine-doped ZnSe yield record low contact resistivities in the order of 10–5 Ω cm2 even at cryogenic temperatures. Finally, making use of the regrowth technique, local Ohmic contacts to ZnSe are demonstrated, which still feature low contact resistivities of (1.4 ± 0.4) × 10–3 Ω cm2 at 4 K. These findings pave the way for new electrical devices in the ZnSe material system such as field-effect transistors, electrostatically defined qubits, or quantum repeaters operating at cryogenic temperatures.

Fabrication and Evaluation of N-Channel GaN Metal-Oxide-Semiconductor Field-Effect Transistors Based on Regrown and Implantation Methods.

We have demonstrated the enhancement-mode n-channel gallium nitride (GaN) metal-oxide field-effect transistors (MOSFETs) on homoepitaxial GaN substrates using the selective area regrowth and ion implantation techniques. Both types of MOSFETs perform normally off operations. The GaN-MOSFETs fabricated using the regrowth method perform superior characteristics over the other relative devices fabricated using the ion implantation technique. The electron mobility of 100 cm2/V·s, subthreshold of 500 mV/dec, and transconductance of 14 μs/mm are measured in GaN-MOSFETs based on the implantation technique. Meanwhile, the GaN-MOSFETs fabricated using the regrowth method perform the electron mobility, transconductance, and subthreshold of 120 cm2/V s, 18 μs/mm, and 300 mV/dec, respectively. Additionally, the MOSFETs with the regrown p-GaN gate body show the Ion/Ioff ratio of approximately 4 × 107, which is, to our knowledge, among the best results of GaN-MOSFETs to date. This research contributes a valuable information for the design and fabrication of power switching devices based on GaN.

Diamond lateral FinFET with triode-like behavior

In this letter we report a diamond lateral FinFET fabricated using an ohmic regrowth technique. The use of ohmic regrowth separates the source/drain and gate fabrication, providing a viable means to improve ohmic contact resistance while protecting the top surface of the diamond channel from dry etch damage. Enabled by high channel quality, the diamond transistor behavior was shown to transit from a pentode-like to a triode-like characteristic when channel length decreased. For the first time, space charge limited transport in diamond FinFETs with a short channel length was demonstrated. We have analyzed the space charge limited transport from room temperature to 150 °C. This space charge limited transport, in combination with improved ohmic contacts, will enable diamond FinFETs for various high-power applications.