Minority Carrier Trap in n-Type 4H–SiC Schottky Barrier Diodes (original) (raw)

Boron-Related Defects in N-Type 4H-SiC Schottky Barrier Diodes

Materials

We report on boron-related defects in the low-doped n-type (nitrogen-doped) 4H-SiC semitransparent Schottky barrier diodes (SBDs) studied by minority carrier transient spectroscopy (MCTS). An unknown concentration of boron was introduced during chemical vapor deposition (CVD) crystal growth. Boron incorporation was found to lead to the appearance of at least two boron-related deep-level defects, namely, shallow (B) and deep boron (D-center), with concentrations as high as 1 × 1015 cm−3. Even though the boron concentration exceeded the nitrogen doping concentration by almost an order of magnitude, the steady-state electrical characteristics of the n-type 4H-SiC SBDs did not deteriorate.

Electrically active defects in SiC Schottky barrier diodes

The electrical properties of deep-level defects in real packaged SiC Schottky barrier rectifiers were studied by deep level transient spectroscopy (DLTS). One deep-level trap with an activation energy in the 0.29–0.30 eV range was revealed to be present in all the tested samples. The electrical characteristics of the trap indicate it is probably attributed to dislocations or to metastable defects, which can be responsible for discrepancies observed in I-V characteristics (see Ref. [2]). KeywordsSiC–Schottky diode–deep-level defect–DLTS

Characterization of 4H-SiC Junction Barrier Schottky Diodes by Admittance vs Temperature Analyses

Materials Science Forum, 2009

Schottky barrier diodes and junction barrier Schottky diodes are investigated by thermal admittance spectroscopy, and by Capacitance-Voltage measurements. Samples are protected with surrounding junction termination extension and p+ ring. Temperature dependence of the doping level is first calculated. Then admittance spectra allow detecting defects and extracting their activation energies and capture cross sections. Results seem to indicate the presence of interfacial defects and defects due to the implantation process.

A Study of Inhomogeneous Schottky Diodes on n-Type 4H-SiC

Materials Science Forum, 2006

We investigated arrays of Ni, Pt, or Ti Schottky diodes on n-type 4H-SiC epitaxial layers using current-voltage ͑I-V͒ measurements, electron beam induced current ͑EBIC͒, polarized light microscopy, x-ray topography, and depth-resolved cathodoluminescence spectroscopy. A significant percentage of diodes ͑ϳ7 % -30% depending on epitaxial growth method and diode size͒ displayed "nonideal" or inhomogeneous barrier height characteristics. We used a thermionic emission model based on two parallel diodes to determine the barrier heights and ideality factors of high-and low-barrier regions within individual nonideal diodes. Whereas high-barrier barrier heights increased with metal work function, low-barrier barrier heights remained constant at ϳ0.60, 0.85, and 1.05 eV. The sources of these nonidealities were investigated with a variety of spectroscopic and imaging techniques to determine the nature and energy levels of the defects. EBIC indicated that clusters of defects occurred in all inhomogeneous diodes. Cathodoluminescence spectra revealed additional peaks in the nonideal diodes at 2.65, 2.40, and 2.20 eV, which complement the low-barrier barrier heights. It is proposed that defect clusters act to locally pin the Fermi level, creating localized low-barrier patches, which account for the inhomogeneous electrical characteristics.

Interface Trap-Induced Nonideality in As-Deposited Ni/4H-SiC Schottky Barrier Diode

IEEE Transactions on Electron Devices, 2015

As-deposited Ni/SiC Schottky diodes often show non-ideal forward conduction characteristics. The ideality can be improved by the formation of a nickel-silicide/SiC interface by annealing at > 650°C. The non-ideal characteristics in asdeposited diodes are generally attributed to Schottky barrier inhomogeneity at the interface. However, recent studies show that highly non-ideal characteristics (n > 1.2) cannot be explained by the existing inhomogeneity models. In this paper, we report the observation of hysteresis patterns in the I-V and C-V characteristics of as-deposited non-ideal diodes. It is argued that the existence of evenly distributed slow, donor-like interface traps can explain the hysteresis and the associated Schottky nonideality. A trap density of 10 8 ∼10 10 cm −2 was estimated from the I-V and C-V hysteresis.

Electrical Characterization of High Energy Electron Irradiated Ni/4H-SiC Schottky Barrier Diodes

Journal of Electronic Materials, 2016

The effect of high energy electron (HEE) irradiation on Ni/4H-SiC Schottky barrier diodes was evaluated by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. Electron irradiation was achieved by using a radioactive strontium source with peak emission energy of 2.3 MeV. Irradiation was performed in fluence steps of 4.9 × 10 13 cm-2 until a total fluence of 5.4 × 10 14 cm-2 was reached. The Schottky barrier height determined from (I-V) measurements was not significantly changed by irradiation while that obtained from (C-V) measurements increased with irradiation. The ideality factor was obtained before irradiation as 1.05 and this value did not significantly change as a result of irradiation. The series resistance increased from 47 Ω before irradiation to 74 Ω after a total electron fluence of 5.4 × 10 14 cm-2. The net donor concentration decreased with increasing irradiation fluence from 4.6 × 10 14 cm-3 to 3.0 × 10 14 cm-3 from which the carrier removal rate was calculated to be 0.37 cm-1 .

Investigation of barrier inhomogeneities in Mo/4H–SiC Schottky diodes

Microelectronic Engineering, 2011

Using current-voltage measurements, we have investigated the electrical behavior of molybdenum on 4H-SiC Schottky diodes of various areas and having different edge terminations consisting of high resistivity guard rings manufactured by carbon ion-implantation.

Junction barrier Schottky diodes in 6H SiC

Solid-State Electronics, 1998

AbstractÐJunction barrier Schottky (JBS) diodes in 6H SiC have been fabricated and characterised electrically. This device, demonstrated in silicon technology, has the advantage of a low forward voltage drop comparable to that of Schottky diodes, as well as a high blocking voltage and low reverse leakage current of a pn junction. This is especially attractive for wide bandgap materials such as SiC in which pn junctions have a large forward voltage drop. The devices were capable of blocking up to 1100 V with a leakage current density of 0.15 A cm À2 , limited by the leakage when the drift region was fully depleted, or breakdown of the SiC material itself. The forward conduction was limited by an onresistance of 20 mO cm 2 , resulting in forward voltage drops of 2.6 V at 100 A cm À2 . #