Hole injection contribution to transport mechanisms in metal/p− /p++and metal/oxide/p− /p++ diamond structures

International audienceHeterostructures such as Schottky diodes and metal/oxide/semiconductor structures are the building blocks of diamond electronic devices. They are able to carry large current densities, up to several kA/cm$^2$, if a heavily boron doped layer (p$^{++}$) is included in the semiconducting stack, thus affording a metallic reservoir of mobile holes close to the lightly doped layer (p$^{-}$). In this work, hole injection effects are evidenced experimentally in the two previously mentioned devices and also simulated numerically. Although the potential barrier height at metal/semiconductor interfaces is a fundamental parameter, a more general approach consists in defining the current density from the product of an effective velocity and carrier concentration at interface. In accordance with experimental results, such a view permits to describe both depletion and accumulation regimes, which indeed can exist at the metallic or oxide interface, and to take into account the increase of the hole concentration above the thermal equilibrium one in the p$^{-}$ layer. The lower the temperature, the larger is this second effect. For sufficiently thin p$^{-}$ layers, typically below 2~$\mu$m, this effect frees device operation from the limitation due to incomplete ionization of acceptors and allows a strong decrease of the specific resistance and forward losses while preserving breakdown voltages in the range 1.4 to 2 kV

Simulation numérique et caractérisation de composants de puissance en diamant

International audienceCet article présente les avancées sur la simulation analytique et numérique de composants de puissance en diamant, ainsi que les problématiques de caractérisation associées. Les modèles spécifiques au diamant ont été implémentés et ont été calibrés en confrontant les résultats de simulation aux dernières données expérimentales existantes. Enfin, un soin particulier a été apporté sur la maîtrise de l'auto-échauffement et de la calibration de la température du composant diamant sous test.  </p

Design of Diamond Power Devices: Application to Schottky Barrier Diodes

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High temperature operation of a monolithic bidirectional diamond switch

International audienceWe report the 250 • C operation of a diamond-based monolithic bidirectional switch. A normally-ON double gate deep depletion MOSFET was fabricated with a 400 nm p-type channel with a boron doping of [N AN D ]= 2.3×10 17 cm −3 and an Al 2 O 3 gate oxide thickness of 50 nm. The I st and III rd quadrants transistor characteristics are successfully measured by controlling the channel conductivity with both gates separately, with a clear ON and OFF state. A threshold voltage around 35 V is obtained with a low minimum gate leakage current of 1.00 × 10 −4 mA/mm at a gate-source bias V GS = 50 V. The bidirectional switch is then obtained by operating the MOSFET in the I st quadrant of each gate setup. This first proof of concept offers a reverse conducting and reverse blocking diamond MOSFET, with only one drift region layer

Metal oxide semiconductor structure using oxygen-terminated diamond.

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Energy-band diagram configuration of Al2O3/oxygen-terminated p-diamond metal-oxide-semiconductor

International audienceDiamond metal-oxide-semiconductor capacitors were prepared using atomic layer deposition at 250 °C of Al2O3 on oxygen-terminated boron doped (001) diamond. Their electrical properties were investigated in terms of capacitance and current versus voltage measurements. Performing X-ray photoelectron spectroscopy based on the measured core level energies and valence band maxima, the interfacial energy band diagram configuration of the Al2O3/O-diamond is established. The band diagram alignment is concluded to be of type I with valence band offset ΔEvΔEv of 1.34 ± 0.2 eV and conduction band offset ΔEcΔEc of 0.56 ± 0.2 eV considering an Al2O3 energy band gap of 7.4 eV. The agreement with electrical measurement and the ability to perform a MOS transistor are discussed

Models and parameters study for diamond electronic devices simulations

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