Evaluation of the characteristics of silicon carbide diodes using transient-IBIC technique (original) (raw)
Related papers
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.
Diamond and Related Materials, 2003
Silicon carbide has recently emerged as an attractive material for ionisation radiation detection. The high band gap and high radiation damage resistance should allow the fabrication of detectors capable to operate at high temperature and in high radiation fields. The development of SiC radiation detectors in the field of spectroscopy imposes severe constraints in the electronic quality and homogeneity of the material. In this work we present an investigation of the charge collection properties of 'detector grade' 4H-SiC Schottky diodes performed by means of the X-ray and ion beam induced charge collection (XBICC and IBIC) techniques. Such techniques allow the minority carrier diffusion length of the material to be evaluated and mapping of the transport properties to be performed with a spatial resolution of the order of 1 mm. The investigated detectors are formed by Schottky contact (Au) on the epitaxial layer and an ohmic contact on the back side of 4H-SiC substrates. IBIC measurements were performed using protons of energy 0.7-1.7 MeV. The IBIC spectra show a complete charge collection generated by ionisation in the depletion region. Similar analysis was also performed in steady state conditions using data from photocurrent measurements carried out at European Synchrotron Radiation Facility using 3 keV photons. IBIC and XBICC maps were obtained by recording the mean pulse height and the mean photocurrent as a function of the photon or ion impact co-ordinates. The analysis of such maps allowed us to individuate the spatial distribution of defects and contact imperfections. ᮊ
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.
Correlation between Leakage Current and Ion-Irradiation Induced Defects in 4H-SiC Schottky Diodes
Materials Science Forum, 2006
The defects formation in ion-irradiated 4H-SiC was investigated and correlated with the electrical properties of Schottky diodes. The diodes were irradiated with 1 MeV Si+-ions, at fluences ranging between 1×109cm-2 and 1.8×1013cm-2. After irradiation, the current-voltage characteristics of the diodes showed an increase of the leakage current with increasing ion fluence. The reverse I-V characteristics of the irradiated diodes monitored as a function of the temperature showed an Arrhenius dependence of the leakage, with an activation energy of 0.64 eV. Deep level transient spectroscopy (DLTS) allowed to demonstrate that the Z1/Z2 center of 4H-SiC is the dominant defect in the increase of the leakage current in the irradiated material.
Local non invasive study of SiC diodes with abnormal electrical behavior
Solid-State Electronics, 2015
In this work, Silicon Carbide Schottky Barrier Diodes (SBDs) were inspected by Infrared Lock-In Thermography to study and determine the origin of structural weak spots resulting from their manufacturing and electro-thermal stressing tests. These spots are frequency modulated following three different approaches representative of the SBDs operating regimes and detected by their infrared emission, as they behave as hot spots. According to thermal results, such weak spots have originated from barrier modification due to the wire-bonding process, non-uniform active area resistance due to bad metallization electrical contact, deep level traps creation due to high energy implantation in the edge termination, and internal propagation of lattice defects during thermal cycling.
Study of 6H–SiC high voltage bipolar diodes under reverse biases
Applied Surface Science, 2001
Silicon carbide presents electrical properties suitable for many applications especially for high voltage devices. 6H-SiC P þ NN þ structures have been fabricated following ISE software simulations in order to block voltages as high as 1.5 kV. In particular, these diodes are realized by surrounding the emitter by a p-type region called junction termination extension (JTE). Electrical characterizations under reverse bias at room temperature and in various environments (air, silicone oil) show a premature breakdown for the protected diodes. This breakdown is localized at the emitter periphery. Optical beam induced current (OBIC) measurements show a peak of photocurrent at the junction edge, indicating the presence of a high electric field. These results show a protection efficiency of 60% of the JTE. An electrical activation of the aluminum dopants implanted in the JTE around 30% is derived from the analysis of the presented results. # 2001 Published by Elsevier Science B.V.
Observation of transient current induced in silicon carbide diodes by ion irradiation
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2003
The high-speed current transients induced in SiC p-n diodes by 9 MeV Ni 2þ and 12 MeV Ni 3þ were measured using transient ion beam induced current (TIBIC). The amplitude of the TIBIC signals increases with increasing bias voltage. The transient current fall-time reduces with increasing bias voltage. These results are attributed to the increase in the electric field and the space-charge region with bias. However, the charge collection efficiency is below 100% even if the depletion width is greater than the Ni ion range. This can be attributed to the large nuclear stopping of Ni and recombination of the highly dense electron-hole pairs in the space-charge region. Our result indicates that pulse height defect (PHD) plays a significant role in the charge collection mechanism in these SiC p-n diodes for highly ionizing particles.
Characterization of Sic by Means of C-V Measurement of Respective Schottky Diode by DLTS
2012
Silicon Carbide (SiC) has been characterized by means of capacitance spectroscopy. The capacitance voltage measurement of respective schottky diode is performed by standard method available in our DLTS setup. The capacitance voltage measurements of SiC are obtained at various temperatures under the similar reverse biasing conditions for material. From these measurements the following parameters were evaluated: The doping concentration of SiC at room temperature was calculated 5.2061×1012 cm-3. Its value increased with increase in temperature and showed no significant temperature effect. The built-in potential calculated for SiC at room temperature was 1.49V. Its value gradually decreased with increase in temperature. The depth profile of SiC became more uniform with increase in temperature and showed no change as the temperature varied from room temperature to lower values. Comparison of the data with the literature showed that the sample was affected by native and/or intrinsic poin...
Microelectronics Journal, 2007
In this work the forward J-V characteristics of 4H-SiC p-in diodes are analysed by means of a physics based device simulator tuned by comparison to experimental results. The circular devices have a diameter of 350 mm. The implanted anode region showed a plateau aluminium concentration of 6 Â 10 19 cm À3 located at the surface with a profile edge located at 0.2 mm and a profile tail crossing the n-type epilayer doping at 1.35 mm. Al atom ionization efficiency was carefully taken into account during the simulations. The final devices showed good rectifying properties and at room temperature a diode current density close to 370 A/cm 2 could be measured at 5 V. The simulation results were in good agreement with the experimental data taken at temperatures up to about 523 K in the whole explored current range extending over nine orders of magnitude. Simulations also allowed to estimate the effect of a different p + doping electrically effective profile on the device current handling capabilities.
Electrical characterization of 6H-SiC grown by physical vapor transport method
Materials Science and Engineering: B, 2009
Deep level transient spectroscopy (DLTS) and capacitance versus voltage (C-V) measurements have been used to study the electrical properties of electron traps in n-type 6H-silicon carbide (SiC) grown by physical vapor transport (PVT) technique, designed as Schottky diodes. Ir Schottky-and Ni ohmic-contacts were deposited by sputtering. Current versus voltage (I-V) measurements showed that sputter deposition of the Schottky contact yields diodes with a reduced barrier height and poor rectification characteristics. Four main electron traps revealed in DLTS spectra have activation energies at 0. 39, 0.41, 0,66, and 0.74 eV below the conduction band. Based on a comparison made with electron traps reported in the literature, we conclude that three of them are well-known traps found in the as-grown or irradiated material. There was no emission signature in the literature to make such a correspondence for the trap at 0.74 eV. Strongly nonhomogenous spatial distribution with a tendency of the trap to accumulation at the surface was found by DLTS and C-V profiling. This together with the fact that the trap at 0.74 eV has not been previously reported in as-grown or processed material makes it possible that the trap is sputter deposition induced defect.