Simulation and experimental results on the forward J–V characteristic of Al implanted 4H–SiC p–i–n diodes (original) (raw)
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Solid-State Electronics, 2015
In this work different experimental current-voltage behaviours of several Al implanted 4H-SiC p-i-n diodes are investigated by means of numerical simulations in a wide range of currents and temperatures. Some devices for which recombination and tunneling are the dominant current processes at all biases are classified as ''leaky'' diodes. The well behaved diodes, instead, show good rectifying characteristics with a current conduction due to tunneling below 1.7 V, recombination between 1.7 V and 2.5 V, and diffusion processes above 2.5 V. At higher current regimes, a series resistance in excess of 1 mX cm 2 becomes the main current limiting factor. Depending on the relative weight between the contact resistances and the internal diode resistance, different temperature dependencies of the current are obtained. A good agreement between numerical and measured data is achieved employing temperature-dependent carrier lifetime and mobility as fitting parameters.
Electrical Characterization of the Forward Currentvoltage of Al Implanted 4H-SIC Pin Diodes
2015
In this work,theforward current-voltagecharacteristics of n-type Al implanted 4H-SiC pin diodeshave been investigated experimentally and by mean of numerical simulations in the 298-378K temperature range. Our simulations were performed using proprietary simulations software. The model parameters to be calibrated in the simulation are the electron and hole minority carriers lifetimes.The measured forward I-V characteristics showed two differentbehaviour, the leaky behaved and well behaved diode. The later diodes were considered for simulation comparison.Employing temperature-dependent carrier lifetimes as a fitting parameter, the simulation indicates that drift layer and bulk carrier lifetime ranging from 10ns to 50ns. We achieved a good agreement between simulations and measured data. The measured and the simulated forward characteristics indicate an ideality factor of about1.3for the region 2.5V-2.78Vand 2.14 in the low injection region. Activation energies of about 1.61eV and 2.51...
Electrical Characterization of Ion-Implanted n+/p 6H-SiC Diodes
Materials Science Forum, 2003
In this work the electrical characterisation of ion implanted n + /p planar SiC diodes is presented. When a silicon dioxide film passivated the surface, the presence of electrically conductive paths among the cathodes of the diodes were detected. Surface morphology investigations and Electron Beam Induced Current (EBIC) analyses allowed us to correlate the conductive paths with grooves induced on the SiC surface by the post implantation annealing. After removing the surface silicon oxide film, the diodes were electrically isolated and their currentvoltage (I-V) and capacitance voltage (C-V) characteristics were evaluated. At 10 V the best diodes had a leakage current density value lower than 5x10-11 A/cm 2 while some other diodes showed a value higher than 1x10-7 A/cm 2. EBIC analyses pointed out a similar defect situation in the base region independently of the leakage current value. So no evidence of a correlation between the presence of electrically active defects and the leakage current behavior was found. The maximum measured value of the breakdown voltage (V B) was of about 280 V. For the best diodes, the ideality factor was 2.1 at low voltages and then reached 1.4 increasing the forward bias, but never got 1 before the series resistance dominated the characteristic. Base and emitter doping concentrations calculated using C-V measurements were in agreement with the expected values.
Superlattices and Microstructures, 2009
The comparison between cathodoluminescence and deep level transient spectroscopy is a powerful tool to analyze the defect formation in implanted materials. In this work aluminium implanted 4H-SiC p + /n diodes are studied. Different structures, implanted with different ion energy and fluencies, are analyzed in order to understand the process related effects. The comparison between the epilayer and the implanted areas shows an increase of the concentration of intrinsic defects in the implanted areas. The 4H-SiC band-edge emission decreases, increasing the aluminium ion dose, due to the enhancement of the lattice disorder, partially recovered by the post-implantation annealing.
P–N Junction creation in 6H-SiC by aluminum implantation
Materials Science and Engineering: B, 1999
Bipolar diodes, protected with junction termination extensions, were processed in 6H-SiC. A 5-fold aluminum implantation was carried out for the main p + -n junction creation, which led to the material amorphization. The recrystallization variation with the annealing temperature and duration is examined in this paper. We performed the Al implantations with opposite energy orders, in order to study their influence on the diode electrical characteristics. The increasing order led to a better forward conduction, and reverse leakage currents more important.
A 4H-SiC p–i–n Diode Fabricated by a Combination of Sublimation Epitaxy and CVD
Semiconductors, 2005
The possibility of fabricating heavily doped ( N a -N d ≥ 1 × 10 19 cm -3 ) p + -4 H -SiC layers on CVD-grown lightly doped n -4 H -SiC layers by sublimation epitaxy has been demonstrated. It is shown that a Au/Pd/Ti/Pd contact, which combines a low specific contact resistance (~2 × 10 -5 Ω cm 2 ) with high thermal stability (up to 700 ° C), is the optimal contact to p-4 H -SiC. The p -n structures obtained are used to fabricate packaged diodes with a breakdown voltage of up to 1400 V.
Journal of Electronic Materials, 2005
Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the hightemperature mask has been demonstrated. Nomarski optical microscopy and scanning electron microscopy (SEM) were used to characterize selective growth of SiC. In addition, 250-µm, square-shaped, p-n junction diodes by selective n-type epitaxial growth on a p-type epilayer were fabricated. The refilled fingers with different width were designed to vary the periphery/area (P/A) ratio. The effects of P/A ratio on the current-voltage (J-V) characteristics have been investigated. The ideality factor extracted from J-V characteristics is Ϸ2 at a temperature range of 25-275°C, which indicates that the Shockley-Read-Hall recombination is the dominant mechanism in the conduction region. The reverse leakage current does not show dependence on P/A ratio for trench-refilled diodes. The room-temperature reverse leakage-current density at 100 V is less than 3.5 ϫ 10 Ϫ7 A/cm 2 for all diodes. Also, the reverse leakage current does not increase significantly with temperature up to 275°C. The breakdown voltages measured at room temperature are about 450 V and 400 V for diodes without and with fingers, respectively.
The Response of High Voltage 4H-SiC P-N Junction Diodes to Different Edge Termination Techniques
MRS Proceedings, 1998
Edge termination is an important aspect in the design of high power p-n junction devices. In this paper, we compare the breakdown characteristics of 4H-SiC p+-n diodes with oxide passivation and with edge termination using either low or high energy ion implantations. N- and p-type epilayers of 4H-SiC were grown by chemical vapor deposition on n+ 4H-SiC wafers. Circular mesa structures of different diameters were patterned and isolated by reactive ion etching. Four types of samples were fabricated. The first group was not implanted or passivated and was left for control. The second type consisted of oxide-passivated diode structures while the third and fourth types were ion implanted with 30 keV Ar+ and 2.2 MeV He+ ions, respectively. The time dependent breakdown characteristics were determined using a fast voltage ramp technique. The reverse bias breakdown voltages and leakage currents of these diodes were different for the different types of the edge termination. Diodes terminated ...