Temperature Coefficient Of Breakdown Voltage Research Articles

Temperature dependence of on–off ratio and reverse recovery time in NiO/β-Ga2O3 heterojunction rectifiers

The temperature-dependent behavior of on/off ratio and reverse recovery time in vertical heterojunction p-NiO/β n-Ga2O/n+ Ga2O3 rectifiers was investigated over the temperature range of 25–300 °C. The device characteristics in forward bias showed evidence of multiple current transport mechanisms and were found to be dependent on the applied bias voltages and temperatures. The on–off ratio decreased from 3 × 106 at 25 °C to 2.5 × 104 at 300 °C for switching to 100 V reverse bias. For 200 μm diameter rectifiers, the reverse recovery time of ∼21 ns was independent of temperature, with the Irr monotonically increasing from 15.1 mA at 25 °C to 25.6 mA at 250 °C and dropping at 300 °C. The dI/dt increased from 4.2 to 4.6 A/μs over this temperature range. The turn-on voltage decreased from 2.9 V at 25 °C to 1.7 V at 300 °C. The temperature coefficient of breakdown voltage was negative and does not support the presence of avalanche breakdown in NiO/β-Ga2O3 rectifiers. The energy loss during switching from 100 V was in the range 23–31 μJ over the temperature range investigated.

A GaAsSb/AlGaAsSb Avalanche Photodiode With a Very Small Temperature Coefficient of Breakdown Voltage

Avalanche photodiodes (APDs) made with the material AlGaAsSb (lattice-matched to InP) exhibit very low excess noise characteristics. We demonstrate a Separate Absorption and Multiplication APD (SAM-APD) incorporating a GaAs <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.52</sub> Sb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.48</sub> (GaAsSb) absorption region and an Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.56</sub> Sb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.44</sub> (AlGaAsSb) avalanche region. Our GaAsSb/AlGaAsSb SAM-APD exhibits a cut-off wavelength of 1.70 μm at room temperature and a responsivity of 0.39 A/W at 1.55 μm wavelength (with no antireflection coating). Temperature dependence of the breakdown voltage was obtained from avalanche gain data from multiple devices operated at 77 to 295 K. This produced a temperature coefficient of breakdown voltage of 4.31±0.33 mV/K, a factor of 10 and 5 smaller than values for comparable InP and InAlAs SAM-APDs. The very small temperature coefficient of this work is consistent with the extremely weak temperature dependence of avalanche breakdown previously observed in AlGaAsSb diodes.

Improvement of parameters of micro-pixel avalanche photodiodes

The paper is concerned with the parameter study of a new generation of micro-pixel avalanche photodiodes (MAPD) with deeply buried pixel structure, also named silicon photomultipliers (SiPM) or multi-pixel photon counter (MPPC). The new MAPD of type MAPD-3NM was manufactured in the frame of collaboration with Zecotek Company. Measurements were carried out and discussed in terms of the important parameters such as the current-voltage and capacitance-voltage characteristic, gain, the temperature coefficient of breakdown voltage, breakdown voltage, and gamma-ray detection performance using an LFS scintillator. The obtained results showed that the newly developed MAPD-3NM photodiode outperformed the previous generation in most parameters and can be successfully applied in space application, medicine, high-energy physics, and security. New proposals are also discussed, for further improvement of the parameters of the MAPD photodiodes that will be produced in the coming years.

60 A/W high voltage GaN avalanche photodiode demonstrating robust avalanche and high gain up to 525 K

This paper presents a demonstration of a 278 V GaN avalanche photodiode offering a photoresponsivity of 60 A/W and capable of operating at high temperature with a high gain of 105. The GaN n–i–p diode fabricated on a free-standing GaN substrate showed robust avalanche, which has not been observed on any GaN avalanche photodiodes (APDs) grown on foreign substrates. Both electrical and optical characterization studies were conducted to validate the occurrence of avalanche in these devices. The device showed a positive temperature coefficient of breakdown voltage, which follows the nature of avalanche breakdown. The positive coefficient was measured to be 3.85 × 10−4 K−1 (0.1 V/K) at a measurement temperature ranging from 300 K to 525 K. The avalanche-induced electroluminescence is also reported here in GaN APDs. The diode demonstrated superior performance by simultaneously offering a high photoresponsivity of 60 A/W, a high gain of 105 up to 525 K, and low dark current (1.5 × 10−5 A/cm2), measured at 0.95 × BV following industry standards.

Analysis of Negative Differential Resistance and Energy Consumption at Transient Surge Response against Winter Lightning for MOVs, ABDs, and TSSs

Abstract surge protective components (SPCs) such as metal oxide varistors (MOVs), avalanche breakdown diodes (ABDs), and thyristor surge suppressors (TSSs) have been widely used in low-voltage power distribution systems, in main AC power lines inside of appliances, electrical, and electronic systems, or signaling and telecommunication lines in ICT equipment to protect them against lightning surges. The maximum transient clamping voltage and surge-handling capability are important parameters to determine the ability of the SPCs. They are determined by the negative differential resistance, which depends on the steepness and wave-tail of the applied lightning surge waveform, especially characterized by winter lightning. The transient surge responses of SPCs were analyzed, and the mechanisms of negative differential resistance were clarified. Negative differential resistance was caused by the lead wire inductance in MOVs, the positive temperature coefficient of breakdown voltage in ABDs, the dependence on temperature of the Auger recombination, and the carrier mobility in TSSs. Clamping voltage and surge-handling capability designs considering inductance in the lead wire and the dependence on temperature during self-heating are important to apply to SPCs so that they can withstand high energy winter lightning with a long wave tail.

Feasibility Study on Silicon Photomultiplier With Epitaxial Quenching Resistors as the Readout for PET Detectors

The silicon photomultiplier (SiPM) with epitaxial quenching resistors (EQR) is a novel SiPM technology currently under research and development. It has distinguished features of simple device structure, high fill factor, high microcell density, large dynamic range, and fast recovery time. In this paper, we report its latest developments aiming at positron emission tomography (PET) applications. The EQR type SiPM with active area of $2.2~\hbox{mm} \times 2.2~\hbox{mm}$ demonstrated a peak PDE of 11.6% at 460 nm, PDE greater than 8.0% at 420 nm, temperature coefficient for breakdown voltage of 16 mV per $^\circ {\rm C}$ , with the fill factor of 40% and microcell density as high as $\sim 9000/\hbox{mm}^{2}$ . We measured a time resolution better than 357 ps FWHM and a 17.5% FWHM energy resolution at 511 keV by 1-to-1 coupling of the device with a $2~\hbox{mm} \times 2~\hbox{mm} \times 10~\hbox{mm}$ lutetium yttrium oxyorthosilicate (LYSO) crystal without any preamplifiers. Those preliminary results show the potential of using such SiPM to build a high spatial resolution and high timing resolution PET system.

ANALYSIS OF ELECTRICAL BEHAVIOR OF SOI LDMOSFET WITH RESPECT TO TEMPERATURE AND DOPING USING T-CAD SIMULATOR

In this paper, the effect of temperature variation and doping variation of p-body on various parameters like Breakdown voltage, on resistance, drain leakage current, threshold voltage etc of SOI laterally diffused MOSFET has been analyzed. Since power mosfet is designed for radio frequency power amplifiers which is used in wireless system-on-a-chip applications. The device is fabricated on a thin-film SOI wafer in order to reduce the leakage current and also prohibit the formation of parasitic diode with substrate. On the basis of analysis we are able to prove that this SOI LDMOSFET has +ve temperature coefficient for breakdown voltage, negative temp coefficient for threshold voltage, positive temperature coefficient for on resistance and +ve temperature coefficient for drain leakage current.

Silicon Substrate Engineered High-Voltage High-Temperature GaN-DHFETs

Low-cost GaN-on-Si-based transistors are targeted to function at high ambient temperatures. With this perspective, it is aimed to evaluate the high-temperature (HT) capabilities of GaN-on-Si double-heterostructure field-effect transistors. It is highlighted that HT device operation degrades both ON and OFF states that are directly related to the increase in the on-resistance and the decrease in device breakdown voltage; 2-DEG mobility drops with increasing temperature and is responsible for ON-state degradation. Regarding the OFF-state operation, it is observed that at low-voltage operation and with increasing temperature, there is an increase in the OFF-state leakage current because of thermal-assisted electrical conduction across the III-N layers and various interfaces. The main breakdown limiting mechanism at any temperature is, however, buffer leakage along the AlN/Si interface. Because this parasitic conduction, a negative temperature coefficient of breakdown voltage of approximately -1 V/°C is observed. For devices after Si removal, the leakage across the AlN/Si interface is interrupted and therefore HT OFF-state characteristics show high potential to be used at high operating voltage. A breakdown voltage as high as ~1800V is observed after Si removal compared with ~500 V with Si at 150°C.

AlAsSb Avalanche Photodiodes With a Sub-mV/K Temperature Coefficient of Breakdown Voltage

The temperature dependence of dark current and avalanche gain were measured on AlAsSb p-i-n diodes with avalanche region widths of 80 and 230 nm. Measurements at temperatures ranging from 77 to 295 K showed that the dark current decreases rapidly with reducing temperature while avalanche gain exhibits a weak temperature dependence. No measurable band to band tunneling current was observed in the thinner diodes at an electric field of 1.07 MV/cm, corresponding to a bias of 95% of the breakdown voltage. Temperature coefficients of breakdown voltage of 0.95 and 1.47 mV/K were obtained from 80 and 230 nm diodes, respectively. These are significantly lower than a range of semiconductor materials with similar avalanche region widths. Our results demonstrated the potential of using thin AlAsSb avalanche regions to achieve low temperature coefficient of breakdown voltage without suffering from high band to band tunneling current.

High temperature and wavelength dependence of avalanche gain of AlAsSb avalanche photodiodes

The evolution of the dark currents and breakdown at elevated temperatures of up to 450 K are studied using thin AlAsSb avalanche regions. While the dark currents increase rapidly as the temperature is increased, the avalanche gain is shown to only have a weak temperature dependence. Temperature coefficients of breakdown voltage of 0.93 and 1.93 mV/K were obtained from the diodes of 80 and 230 nm avalanche regions (i-regions), respectively. These values are significantly lower than for other available avalanche materials at these temperatures. The wavelength dependence of multiplication characteristics of AlAsSb p-i-n diodes has also been investigated, and it was found that the ionization coefficients for electrons and holes are comparable within the electric field and wavelength ranges measured.

Temperature Dependence of Avalanche Breakdown in InP and InAlAs

Simple analytical expressions for temperature coefficients of breakdown voltage of avalanche photodiodes (APDs) utilizing InP or InAlAs are reported. The work is based on measurements of temperature dependence of avalanche breakdown voltage in a series of InP and InAlAs diodes at temperatures between 20 and 375 K. While avalanche breakdown voltage becomes more temperature sensitive with avalanche region thickness for both materials, the InAlAs diodes are less sensitive to temperature changes compared to InP diodes.

High Temperature Operation of Silicon Carbide Schottky Diodes with Recoverable Avalanche Breakdown

4H-SiC diodes with nickel silicide (Ni2Si) and molybdenum (Mo) Schottky contacts have been fabricated and characterised at temperature up to 400°C. Room temperature boron implantation has been used to form a single zone junction termination extension. Both Ni2Si and Mo diodes revealed unchanging ideality factors and barrier heights (1.45 and 1.3 eV, respectively) at temperatures up to 400°C. Soft recoverable breakdowns were observed both in Ni2Si and Mo Schottky diodes at voltages above 1450 V and 3400 V depending on the epitaxial structure used. These values are about 76% and 94% of the ideal avalanche breakdown voltages. The Ni2Si diodes revealed positive temperature coefficients of breakdown voltage at temperature up to 240°C.

Growth and characterization of GaN PiN rectifiers on free-standing GaN

GaN PiN rectifiers with high structural quality were grown on free-standing GaN substrates using metalorganic chemical vapor deposition. The lattice mismatch between the substrate and the epitaxial GaN was found to be ∼1×10−4. The full width at half maximum of the (0002) rocking curve was 79arcs compared to 230arcs for similar materials grown on sapphire. The incorporation of C, H, and O impurities in the homoepitaxial drift layer was reduced by a factor of 2–4. The rectifiers on GaN demonstrated rectification to −265V, which represents a 1.6× improvement over the rectifiers on sapphire and corresponds to a critical electric field ∼2.7MV∕cm. The homoepitaxial rectifiers also showed two orders of magnitude lower reverse leakage and a smaller negative temperature coefficient for breakdown voltage, consistent with a reduced defect density in the drift region.

Avalanche phenomena in 4H-SiC p-n diodes fabricated by aluminum or boron implantation

Characteristics of p-n junction fabricated by aluminum-ion (Al/sup +/) or boron-ion (B/sup +/) implantation and high-dose Al/sup +/-implantation into 4H-SiC (0001) have been investigated. By the combination of high-dose (4/spl times/10/sup 15/ cm/sup -2/) Al/sup +/ implantation at 500/spl deg/C and subsequent annealing at 1700/spl deg/C, a minimum sheet resistance of 3.6 k/spl Omega///spl square/ (p-type) has been obtained. Three types of diodes with planar structure were fabricated by employing Al+ or B+ implantation. B/sup +/-implanted diodes have shown higher breakdown voltages than Al/sup +/-implanted diodes. A SiC p-n diode fabricated by deep B+ implantation has exhibited a high breakdown voltage of 2900 V with a low on-resistance of 8.0 m/spl Omega/cm/sup 2/ at room temperature. The diodes fabricated in this study showed positive temperature coefficients of breakdown voltage, meaning avalanche breakdown. The avalanche breakdown is discussed with observation of luminescence.

The Temperature Dependent Breakdown Voltage For 4H- and 6H-SiC Diodes

ABSTRACTThe breakdown voltages of 6H- and 4H-SiC rectifiers as function of temperature were modeled analytically in both non-reachthrough diode and reachthrough diode. The breakdown voltage was derived by the ionization integral employing accurate hole impact ionization coefficient. The breakdown voltage of SiC rectifiers was increased with increasing temperature and the positive temperature coefficient of breakdown voltage indicates that SiC rectifiers are suitable for high temperature applications. The breakdown voltages of both 6H- and 4H-SiC diodes were increased by M(T)-1/4 in NRDs and M(T)-1/8 in RDs.

Study of bulk and elementary screw dislocation assisted reverse breakdown in low-voltage (&amp;gt;250 V) 4H-SiC p/sup +/-n junction diodes. II. Dynamic breakdown properties

For Part I see ibid., vol.46, no.3, pp.478-84 (Mar. 1999). This paper outlines the dynamic reverse-breakdown characteristics of low-voltage (<250 V) small-area <5/spl times/10/sup -4/ cm/sup 2/ 4H-SiC p/sup +/-n diodes subjected to nonadiabatic breakdown-bias pulsewidths ranging from 0.1 to 20 /spl mu/s 4H-SiC diodes with and without elementary screw dislocations exhibited positive temperature coefficient of breakdown voltage and high junction failure power densities approximately five times larger than the average failure power density of reliable silicon pn rectifiers. This result indicates that highly reliable low-voltage SiC rectifiers may be attainable despite the presence of elementary screw dislocations. However, the impact of elementary screw dislocations on other more useful 4H-SiC power device structures, such as high-voltage (>1 kV) pn junction and Schottky rectifiers, and bipolar gain devices (thyristors, ICBT's, etc.) remains to be investigated.

Role of defects in producing negative temperature dependence of breakdown voltage in SiC

Electron beam induced current (EBIC) techniques were employed in order to understand the role of defects on the breakdown characteristics of SiC. EBIC images revealed that certain defects caused enhanced multiplication leading to the catastrophic failures in SiC diodes. The impact ionization coefficients for holes measured at the defective site (αp,eff) were found to be higher than those measured at a nondefective site. Also, αp,eff measured at the defective site was found to increase with increasing temperature in contrast with a defect free diode where αp decreases with increasing temperature, clearly indicating that the defects produce the observed negative temperature coefficient of breakdown voltage in SiC.

High Voltage Silicon Carbide Devices

ABSTRACTProgress made in the development of high performance power rectifiers and switches from silicon carbide are reviewed with emphasis on approaching the 100-fold reduction in the specific on-resistance of the drift region when compared with silicon devices with the same breakdown voltage. The highlights are: (a) Recently completed measurements of impact ionization coefficients in SiC indicate an even higher Baliga's figure of merit than projected earlier. (b) The commonly reported negative temperature co-efficient for breakdown voltage in SiC devices has been shown to arise at defects, allaying concerns that this may be intrinsic to the material. (c) Based upon fundamental considerations, it has been found that Schottky rectifiers offer superior on-state voltage drop than P-i-N rectifiers for reverse blocking voltages below 3000 volts. (d) Nearly ideal breakdown voltage has been experimentally obtained for Schottky diodes using an argon implanted edge termination. (e) Planar ion-implanted junctions have been successfully fabricated using oxide as a mask with high breakdown voltage and low leakage currents by using a filed plate edge termination. (f) High inversion layer mobility has been experimentally demonstrated on both 6H and 4H-SiC by using a deposited oxide layer as gate dielectric. (g) A novel, high-voltage, normally-off, accumulation-channel, MOSFET has been proposed and demonstrated with 50x lower specific on-resistance than silicon devices in spite of using logic-level gate drive voltages. These results indicate that SiC based power devices could become commercially viable in the 21st century if cost barriers can be overcome.

Non-Micropipe Dislocations in 4H-SiC Devices: Electrical Properties and Device Technology Implications

ABSTRACTIt is well-known that SiC wafer quality deficiencies are delaying the realization of outstandingly superior 4H-SiC power electronics. While efforts to date have centered on eradicating micropipes (i.e., hollow core super-screw dislocations with Burgers vectors &gt; 2c), 4H-SiC wafers and epilayers also contain elementary screw dislocations (i.e., Burgers vector = lc with no hollow core) in densities on the order of thousands per cm 2, nearly 100-fold micropipe densities. While not nearly as detrimental to SiC device performance as micropipes, it has been previously shown that diodes containing elementary screw dislocations exhibit a 5% to 35% reduction in breakdown voltage, higher pre-breakdown reverse leakage current, softer reverse breakdown I-V knee, and concentrated microplasmic breakdown current filaments when measured under DC testing conditions. This paper details the impact of elementary screw dislocations on the experimentally observed reverse-breakdown pulse-failure characteristics of low-voltage (&lt; 250 V) small-area (&lt; 5 × 10-4 cm2) 4H-SiC p+n diodes. The presence of elementary screw dislocations did not significantly affect the failure properties of these diodes when subjected to non-adiabatic breakdown-bias pulsewidths ranging from 0.1 μs to 20 μs in duration. Diodes with and without elementary screw dislocations exhibited positive temperature coefficient of breakdown voltage and high junction failure power densities well above the failure power densities exhibited by highly reliable silicon power rectifiers. This preliminary result, based on measurements from one wafer of SiC diodes, suggests that highly reliable low-voltage SiC rectifiers may be attainable despite the presence of elementary screw dislocations.

Positive temperature coefficient of breakdown voltage in 4H-SiC pn junction rectifiers

It has been suggested that once silicon carbide (SiC) technology overcomes some crystal growth obstacles, superior SiC semiconductor devices would supplant silicon in many high-power applications. However, the property of positive temperature coefficient of breakdown voltage, a behavior crucial to realizing excellent power device reliability, has not been observed in 4H-SiC, which is presently the best-suited SiC polytype for power device implementation. This paper reports the first experimental measurements of stable positive temperature coefficient behavior observed in 4H-SiC pn junction rectifiers. This research indicates that robust 4H-SiC power devices with high breakdown reliability should be achievable after SiC foundries reduce material defects such as micropipes, dislocations, and deep level impurities.