We have made AlGaN∕GaN high electron mobility transistors with a Si3N4 passivation layer that was deposited in situ our metal-organic chemical-vapor deposition reactor the same growth sequence as rest of stack. The is shown to be quality and stoichiometric composition. It reduces relaxation, cracking, surface roughness AlGaN layer. also neutralizes charges at top interface, which leads higher two-dimensional electron-gas density. Moreover, it protects during processing improves Ohmic source...

Polycrystalline diamond (PCD) was grown onto high-k dielectric passivated AlGaN/GaN-on-Si high electron mobility transistor (HEMT) structures, with film thicknesses ranging from 155 to 1000 nm. Transient thermoreflectance results were combined device thermal simulations investigate the heat spreading benefit of layer. The observed conductivity (κDia) PCD films is one-to-two orders magnitude lower than that bulk and exhibits a strong layer thickness dependence, which attributed grain size...

Ultrathin-barrier normally off AlN/GaN/AlGaN double-heterostructure field-effect transistors using an in situ SiN cap layer have been fabricated on 100-mm Si substrates for the first time. The high 2DEG density combination with extremely thin barrier leads to enhancement-mode devices state-of-the-art of specific on-resistance that is as low 1.25 m¿·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and breakdown voltage 580 V at <i...

A standard metallization scheme for the formation of Ohmic contacts on n-type GaN does exist. It has following multilayer structure: Ti∕Al∕metal∕Au. Ti is known to extract N out GaN. This leaves a high density vacancies (donors) near interface pinning Fermi level. The created tunnel junction responsible an contact behavior. Au deposited as final metal layer exclude oxidation and should limit diffusion into layers below vice versa. Al in improve resistance, but reason why not been reported...

AlGaN/GaN/AlGaN double heterostructure field-effect transistors (DHFET) with high breakdown voltage and low on-resistance were fabricated on silicon substrates. A linear dependency of the buffer thickness Aluminium concentration was found. as 830 V an 6.2 Ω·mm obtained in devices processed 3.7 µm thickness. The gate–drain spacing 8 did not have any field plates.

We demonstrate a high-voltage low on-resistance AlN/GaN/AlGaN double heterostructure grown by metal–organic chemical vapor deposition on silicon (111) substrate using total buffer thickness of less than 2 µm. A fully scalable local removal technique was developed to dramatically enhance the off-state breakdown voltage transistors. The three-terminal these devices gate–drain distance 15 µm increased significantly, from 750 V 1.9 kV, after removal. high two-dimensional electron gas carrier...

Abstract GaN epitaxially grown on Si is a material for power electronics that intrinsically shows high density of dislocations. We show by Conductive Atomic Force Microscopy (C-AFM) and Defect Selective Etching even materials with similar total dislocation densities substantially different subsets dislocations screw component act as current leakage paths within the AlGaN barrier under forward bias. Potential reasons are discussed it will be directly shown an innovative experiment voltage...

High power electronics using wide bandgap materials are maturing rapidly, and significant market growth is expected in a near future. Ultra materials, which have an even larger than GaN (3.4 eV), represent attractive choice of to further push the performance limits devices. In this work, we report on fabrication AlN/AlGaN/AlN high-electron mobility transistors (HEMTs) 50% Al-content AlGaN channel, has much wider commonly used channel. The structure was grown by metalorganic chemical vapor...

AlGaN/GaN high electron mobility transistors (HEMT) on sapphire substrates have been studied for their potential application in RF power applications; however, the low thermal conductivity of substrate is a major drawback. Aiming at system-in-a-package, authors propose flip-chip-integration approach, where generated heat dissipated to an AlN carrier substrate. Different flip-chip-bump designs are compared, using simulations, electrical measurements, micro-Raman spectroscopy, and infrared...

The breakdown mechanism in GaN-based heterostructures (HFETs) grown on silicon substrate is investigated detail by TCAD simulations and removal technique. High-voltage electrical measurements show that the voltage saturates for larger gate-drain distances. This failure dominated avalanche Si substrate. of AlGaN/GaN/Si structures higher impact ionization factor electron density at interface indicating a leakage current path where occurs. Experimentally, etching off no longer linearly...

AlGaN/GaN high electron mobility transistors (HEMTs) grown on 150 mm Si(111) substrates are reported in this work. The sheet resistance of the HEMT structure is as low 260 ±3.4 Ω/□. range 1560–1650 cm2 V-1 s-1. crack-free mirror-like wafers were obtained by using a simple AlGaN/AlN buffer. mechanism for dislocation reduction GaN above buffer presented density around (1.5–2.5)×109/cm2. Some processed and current close to 1 A/mm was achieved. maximum transconductance 270 mS/mm on-state 2.6 Ω mm.

In this letter, we present a novel approach to enhance the breakdown voltage <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$(V_{\rm BD})$</tex></formula> for AlGaN/GaN/AlGaN double-heterostructure FETs (DHFETs), grown by metal–organic chemical vapor deposition on Si (111) substrates through silicon-substrate-removal and layer-transfer process. Before removing substrate, both buffer isolation test...

Using a generalized extraction method, the fixed charge density Nint at interface between in situ deposited SiN and 5 nm thick AlGaN barrier is evaluated by measurements of threshold voltage Vth an AlGaN/GaN metal insulator semiconductor high electron mobility transistor as function thickness. The thickness originally 50 layer reduced dry etching. extracted order polarization density. total removal cap leads to complete depletion channel region resulting = +1 V. Fabrication gate stack with...

Gallium nitride on silicon (GaN/Si) is an important technological approach for power electronic devices exhibiting superior performance compared to based a pure technology. However, the material defect density in GaN/Si high, and identification of critical defects limiting device reliability still only partially accomplished because experimental difficulties. In this work, atomic force microscopy, scanning electron secondary ion mass spectrometry, cathodoluminescence were employed...

We discuss possibilities of adjustment a threshold voltage VT in normally off GaN high-electron mobility transistors (HEMTs) without compromising maximal drain current IDSmax. Techniques low power plasma or thermal oxidation 2-nm thick AlN cap over 3-nm AlGaN barrier are developed and calibrated for thorough the with minimal density surface donors at inherent oxide-semiconductor interface. It has been shown that while technique leads to channel and/or interface degradation, scalability...

The effect of surface passivation on two-dimensional electron gas (2DEG) carrier density in undoped AlGaN/GaN heterostructures is investigated by capacitance–voltage (C–V) measurements. All oxides used (SiO2, Al2O3, and Ta2O5) experienced a decrease 2DEG concentration with increasing thickness the respective oxide layers between gate AlGaN layer. In contrast, increased markedly Si3N4 layer thickness. An elementary polarization model was to fit behavior for all materials thicknesses leading...

Abstract AlGaN is an important material for ultra‐violet light emitters, photo detectors and high breakdown voltage switching devices. In this work, crack‐free Al x Ga 1‐x N (5% &lt; 55%) layers up to 1.5 μm have been grown on 4 inch Si(111) using AlN/Al y 1‐y (y &gt; 70%) template. The structural quality of comparable that GaN silicon(111). For 0.16 0.84 N, the FWHM HR‐XRD (0002) (‐1102) ω‐scan around 650 arc sec 1200 respectively. Based buffer, a double heterostructure (DH) FET was...

Abstract Gallium nitride based high electron mobility transistors offer carrier density combined with and enable operation at frequencies, voltages temperatures. However, they are generally working in depletion mode, requiring a negative bias to switch them off. As this is disadvantageous for circuit design, power consumption safety of operation, enhancement mode devices would be favourable. This can reached by shifting the threshold voltage towards more positive values implantation...

We describe the fabrication and characteristics of high voltage enhancement mode SiN/AlGaN/GaN/AlGaN double heterostructure FET devices. The Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> not only acts as a passivation layer but is crucial in device concept it an electron donating (1). By selective removal under gate in-situ SiN, we realize e-mode operation with very narrow...

Abstract We report high breakdown combined with low on‐resistance results on AlGaN/GaN/AlGaN double heterostructure devices (DHFET) grown 4 inch Silicon substrates. On two fingers gate‐drain distance (L GD ) of 8 μm we measured a voltage (V BD 650 V and an (R 7.2 Ω·mm. also demonstrated that increasing the buffer thickness etching deep into AlGaN layer improve both device breakdown. Moreover, have achieved (580 V) for smaller L (5 μm) lowest reported (6 Ω·mm) this range. (© 2009 WILEY‐VCH...

The aim of this work is to investigate the breakdown mechanisms layers constituting vertical buffer GaN-on-Si HEMTs; in addition, for first time we demonstrate that field AlN nucleation layer grown on a silicon substrate equal 3.2 MV/cm and evaluate its temperature dependence. To aim, three samples, obtained by stopping epitaxial growth GaN Silicon stack at different steps, are studied compared: Si/AlN, Si/AlN/AlGaN, full up Carbon doped layer. current-voltage (IV) characterizations...

We investigated the limitations of field plate (FP) effect on breakdown voltage <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:xlink="http://www.w3.org/1999/xlink">BD</sub> that is due to silicon substrate in AlGaN/GaN/AlGaN double heterostructures field-effect transistors. In our previous work, we showed devices with large gate-drain distance (L xmlns:xlink="http://www.w3.org/1999/xlink">GD</sub> > 8 μm), does not linearly...