Diode Temperature Research Articles

Cooling of Semiconductor Devices via Quantum Tunneling.

Classical transport of electrons and holes in nanoscale devices leads to heating that severely limits performance, reliability, and efficiency. In contrast, recent theory suggests that interband quantum tunneling and subsequent thermalization of carriers with the lattice results in local cooling of devices. However, internal cooling in nanoscale devices is largely unexplored. Here, using a novel scanning thermal microscopy technique with millikelvin temperature resolution and nanometer spatial resolution, we directly record the cross-sectional temperature in functional InGaAs tunnel diodes. Our measurements reveal large, localized cooling of 2-3 W/cm^{2} at the tunnel junction, which is in quantitative agreement with the bipolar Peltier process associated with interband tunneling. These advances hold significant potential for integration into electronic and energy conversion devices and improving their performance.

Effect of filer content on the thermal characteristics of underfill materials for Ball-Grid-Array component package

High-density integration and fast processing speed in the semiconductor industry have increased heat generation in electronic devices. Underfill materials, known for their high thermal conductivity and low coefficient of thermal expansion (CTE), offer a potential solution to dissipate heat and improve device reliability. In this study, we investigate the effect of filler content on the thermal reliability of underfill materials for ball grid array (BGA) component packaging. Mainly, we investigate the thermal conductivity, CTE, and mechanical properties of different filler contents of Al2O3 and Al2O3–BN hybrid underfills to facilitate heat dissipation and improve device reliability. The thermal conductivity of the underfill materials was evaluated by measuring the surface temperatures of underfill molded flip-chip light-emitting diodes (FCLEDs). The mechanical properties and thermo-mechanical reliability of the underfill materials were evaluated via a three-point bending test of the underfill packaged BGA components after the thermal shock test. The results showed that optimizing underfill properties based on specific application environments is crucial for obtaining enhanced thermal reliability and mechanical properties of underfill packaged BGA components.

Properties of InSb photodiodes fabricated by ion implantation

InSb photodiodes were fabricated by ion implantation method. The electrical and photoelectrical properties of the photodiodes in the operating temperature range of 69…115 K were investigated. The test structures were fabricated as a part of the developed technological route. The value R0 A0, which is the product of the dynamic resistance and the diode area, was ~2·104 Ohm·cm2 at the operating temperature of 77 K for the diodes with the topological area of 0.01 mm2. The avalanche effect as well as the influence of background radiation on the I–V characteristics and dynamic resistance of the diodes were observed. The integrated ampere-watt responsivity of the fabricated InSb photodiodes to a radiant exitance of a blackbody with the temperature of 500 K was determined. The operating temperature of the InSb diode, at which the thermal and fractional noises were equal to each other, was 115 K under the conditions of the presence of background radiation with the temperature of 293 K in the aperture angle FOV ~ 30°.

Indirect thermographic die temperature measurement of a SiC-based semiconductor diode under the conditions of natural and forced convection

ABSTRACT Information about the die temperature of a semiconductor diode is important to the designer. The shape of the current-voltage characteristics of the semiconductor diode and its operating parameters depend on the value of this temperature. Semiconductor devices that conduct a high current can reach high die and case temperatures. This temperature can be determined by thermographic temperature measurement. The temperature value of the semiconductor diode case will depend on the conditions under which it is operated. For many semiconductor devices, the temperature difference between the case and the die will depend on the convection. Research work was carried out to determine the difference between the die temperature of the semiconductor diode made on the basis of SiC FFSH10120A and its case. The method of making a thermographic temperature measurement of the case of a semiconductor element has been presented and the place where this measurement should be made has been indicated. It was found that in the case of natural convection, the largest difference between the temperature of the semiconductor element and the temperature of its case was 40.1 K. For forced convection, the largest difference between these temperatures was 33.1 K for v = 0.75 m/s and 23.9 K for v = 1.5 m/s.

Design of Laser-Powered Opto-Electrical Current Transformer and Its Application in Electrical Automation of Substations

The novel power equipment represented by the Opto-Electrical Current Transformer (OECT) possesses unparalleled advantages compared to traditional Current Transformers (CTs), rendering it with vast potential in power systems. In the design of OECT, this study employs laser power supply and focuses on the overall perspective, particularly the design of the laser power supply module and the optical fiber digital transmission module. The laser power supply module selects a high-power semiconductor laser to provide power to the circuit, incorporating line filters, thermistor resistors, and a laser overcurrent protection circuit. An automatic temperature control circuit based on PI regulation is utilized to stabilize the working temperature of the laser diode (LD). The photoelectric conversion device PPC-6E achieves a maximum photoelectric conversion efficiency of 40%, and the MAX639 DC–DC conversion chip ensures stable output voltage. The optical fiber digital transmission module adopts a circuit composed of multiple NOR gate logic for electro-optical conversion, a low-power driving circuit based on the 74LVC1G07 chip, and the HFBR-2412 photoelectric converter to simplify the circuit board design. To achieve a higher communication baud rate, a quartz multimode optical fiber with a diameter of 62.5 μm is chosen. In the experimental phase, a simulation of high-power AC power with equal turns is conducted. The linearity/temperature test results demonstrate that the designed OECT in this study meets expectations. In the electrical automation test of substations, a comparison between traditional CTs and the designed OECT is carried out using traditional protection algorithms and optical differential protection algorithms. The results indicate that, compared to traditional protection algorithms, the optical differential algorithm using the designed OECT achieves faster protection times.

Distribution of impurities in base-depleted region of diode temperature sensor

The performance of diode temperature sensors depends on their base-depleted region thickness and impurity distribution profile. In this article, we study the boron diffusion process in the thin base region with a thickness of about 1 μm. We show that, for the proposed p+–n–p temperature sensor structure, the impurity distribution in the n region has the form of an asymmetric parabola, with an extreme concentration point shifted towards the “upper” p+ region.

Switchable Faraday laser with frequencies of 85Rb and 87Rb 780 nm transitions using a single isotope 87Rb Faraday atomic filter

In the development of atomic physics, laser sources with Frequencies corresponding to atomic transition and high stability are essential. The Faraday laser is a special diode laser using the Faraday anomalous dispersion optical filter (FADOF) to realize frequency selection, so the output laser frequency is automatically limited to the atomic Doppler broadening. However, the frequency of a Faraday laser corresponds to the range around only one atomic hyperfine transition. Here, we realize a switchable Faraday laser with two isotopes laser frequencies corresponding to 85Rb 52S1/2 (F=3)→52P3/2 and 87Rb 52S1/2 (F=2)→52P3/2 transitions based on a single isotope 87Rb-FADOF. The laser has good robustness against the fluctuation of diode current and temperature, with wavelength fluctuating within 0.8 pm from 16 to 30 °C of diode temperature, and has a free-running linewidth of 18 kHz. We also lock the laser frequency to the two cycling transitions of 85Rb 52S1/2 (F=3)→52P3/2 (F′=4) and 87Rb 52S1/2 (F=2)→52P3/2 (F′=3) by the modulation transfer spectroscopy technique. The Allan deviation of the residual error signal is 3×10−14/τ, and the frequency stability of the beat detection reaches 2.8×10−12 at 1 s integration time. This 780 nm switchable Faraday laser expands the application scenarios of Faraday lasers, which can be used in laser cooling atoms, optical frequency standards, and other quantum precision measurement fields.

Determination of the Temperature and Thermal Resistance of a Half-Disk Laser Diode by Measuring Pulsed Current-Voltage Characteristics

Determination of the Temperature and Thermal Resistance of a Half-Disk Laser Diode by Measuring Pulsed Current-Voltage Characteristics

Reverse-bias current hysteresis at low temperature in GaN Schottky barrier diodes

In this paper, we report an analysis of reverse current mechanisms observed in GaN Schottky barrier diodes leading to hysteretic behavior of the I–V curves at low temperature. By means of DC measurements from 33 to 475 K, we demonstrate the presence of two leakage mechanisms when comparing the experiments with the results obtained using a unified model to predict the ideal reverse current of the diode. Poole–Frenkel emission is the dominant mechanism for temperatures above 200 K, while trap-assisted tunneling prevails for lower temperatures, where also, hysteresis cycles are revealed by means of DC dual-sweep voltage measurements. The energy of the corresponding traps has also been determined, being around 0.2 and 0.45 eV, respectively. The hysteresis phenomenon is attributed to the bias-induced occupancy of the energy states originating the leakage-current processes, which leads to the reduction of the reverse current after a high negative voltage is applied to the diode.

Mechanism and rule of microwave pulse response of two-stage PIN limiter

<sec>This paper aims to analyze the failure mechanism of the two-stage PIN limiter after having been injected by a microwave pulse. A two-stage PIN limiter model with high computational efficiency and accuracy is built by using the method of field-circuit collaborative simulation. Using this model, the temperature change of the PIN diodes during the injection of microwave pulse is simulated. The melting temperature of the PIN diode is selected as the failure criterion of the PIN limiter. The time and energy required for the failure of the PIN limiter under injection of microwave pulses with different frequencies and amplitudes are simulated. Furthermore, the mechanisms that trigger off these effects are analyzed. The relationship between the microwave pulse parameters and the PIN limiter failure time is summarized by using an empirical formula.</sec><sec>According to the simulation results, the temperature change of the second-stage PIN diode is relatively small compared with that of the first-stage. During the injection of the microwave pulse, the failure time and energy consumption of limiter show a certain regularity with the variation of microwave pulse amplitude and frequency, and this work discusses this regularity from the following three aspects. Firstly, the failure time and energy consumption decrease in a similar trend with frequency increasing. And with the increase in signal amplitude, the failure time and energy consumption tend to stabilize. Secondly, the increase in the signal amplitude leads failure time to decrease, which is similar to the relationship between failure time and the signal frequency mentioned before. But as the signal’s amplitude increases, the energy consumption first increases and then decreases slightly when the amplitude reaches about 900 V. Based on the theoretical analysis and the physical image of the two-stage PIN limiter, the reasons for these effects can be explained as the changes in the I-region's impedance and heat distribution change caused by electric field changes. Thirdly, the failure time and energy consumption show different sensitivities to different parameters of the microwave pulse. The signal frequency change has greater influence on the energy consumption than the signal amplitude change, while the amplitude change can exert a greater influence on the failure time than the frequency change.</sec>

Compact optically pumped magnetometer light source stabilization with regulated feedbacks

Optically pumped magnetometers (OPMs) are very sensitive to magnetic field and have the advantages of portability and low cost. In the miniaturized OPM, a vertical cavity surface emitting laser (VCSEL) diode is utilized to generate the laser light for both pumping and probing, the stability of which significantly affects the sensor’s performance. Therefore, precisely control of the light source is required. This paper proposes a novel method of stabilizing the laser diode output by using a close-loop control with two feedbacks, namely: the measurement of the diode temperature and the output signal of the photodetector. The control coefficients of these two feedbacks are regulated dynamically according to the operating state of the OPM. The experimental results show that after operating for 1000 s, the Allan deviation of the photodetector signal is 3.98 ×10−4 for the proposed method, as a comparison, the Allan deviation is 2.56 ×10−2 for a conventional close-loop control technology. The proposed method performs better for long-time operations. A compact OPM is developed and tested, which employ the proposed scheme to control the output of the VCSEL diode. The experiment results show that a sensitivity of 16 fT/Hz1/2 @ 10 Hz is achieved and the OPM can operate stably in a long time.

An atomic filter laser with a compact Voigt anomalous dispersion optical filter

The study of atomic physics has been greatly influenced by the development of high-stability diode lasers whose output corresponds to the atomic transition. Recently, an atomic filter laser “Faraday laser” shines on stage, owing to its great robustness to the fluctuation of the diode parameters and potentially higher tolerance to vibration. However, cost reduction and portability require the Faraday laser to have a more compact structure. Here, we report on the development of a promising atomic filter laser—a “Voigt laser”—using a Voigt anomalous dispersion optical filter (VADOF) as the frequency-selective element, which has a structural advantage in miniaturization. The influencing factors toward the VADOF are investigated in detail to produce a parameter set for the best performance of a Voigt laser. In this case, the Voigt laser has great robustness to the fluctuation in the diode current and temperature, where the wavelength fluctuation is ±0.5 pm with the variation of the diode parameters (diode current: 73–150 mA and diode temperature: 12–30 °C). In addition, the wavelength of the Voigt laser fluctuates about ± 0.5 pm for 48-h free-running operation and shows excellent reproducibility without manual adjustment. The laser system developed here provides a stable and reliable laser source for substantially improving existing technologies such as the atomic clock, electromagnetically induced transparency, and laser cooling of atoms.

Steppingstone-inspired construction of high vertical thermal conductivity material with low carbon fiber content

Thermal interface materials (TIMs) with good thermal conductivity are paramount in mitigating the heat concentration challenges encountered during the operation of highly integrated components in sophisticated electronic devices. To optimize the comprehensive performance of TIMs, a balance must be struck: minimizing the filler concentration to attenuate materials hardness while maximizing filler content to bolster the thermal conduction pathway. Drawing inspiration from the orientation of tree branches passing through steppingstones in river, a method was proposed in this study. This method exploits the shear effect of carbon fiber (CF), owing to viscosity variances during diameter extrusion, and the differential flow velocity between CF and alumina to induce a significant degree of orientation. Combined with subsequent flipping and bonding, a TIM with vertically oriented CF was prepared. The TIM was obtained with a mere 12.1 wt% CF incorporation, the composite exhibits a through-plane thermal conductivity of 21.29 W/(m·K), representing an enhancement of two orders of magnitude relative to pristine silicone rubber, while retaining its flexibility and deformability. The orientation degree and high efficiency orientation effect of CF have been characterized via scanning electron microscopy (SEM), thermal conductivity test and light-emitting diode (LED) temperature rise test.

Online Monitoring Method of P-I-N Diode Temperature Based on Maximum Recovery Current

The P-i-N diode is as important as insulated gate bipolar translators (IGBTs) in power electronic devices, and its junction temperature is a significant indicator when evaluating the reliability of power electronics. Thus, an online junction temperature monitoring method with the maximum recovery current for P-i-N diodes is proposed in this paper. Firstly, the relationship among maximum recovery current, on-state current and junction temperature of diode has been deduced in theory. The linear correlation among the maximum recovery current, temperature, and on-state current have been illustrated. Secondly, a sampling circuit based on a current transformer has been designed. And then, the mathematical model of junction temperature online monitoring based on the maximum recovery current and sampling circuit has been obtained. Finally, the experimental platform based on the DSP TMS320F28335 has been developed. The experimental results verify the correctness of the relationship among maximum recovery current, on-state current and junction temperature of the diode, and high accuracy of the proposed online monitoring method in practice application, where the maximum temperature error and error percentage are 4.7℃ and 4.49%, respectively. In addition, the proposed method has advantages of simplicity, small size, low cost, convenient installation, and high linearity.

Yb-Doped All-Fiber Amplifier with Low-Intensity Noise in mHz Range Oriented to Space-Borne Gravitational Wave Detection

We present a low-intensity noise single-frequency Yb-doped all-fiber amplifier oriented to space-borne gravitational wave detection. Relative intensity noise (RIN) below −70 dBc/Hz @ 1 mHz~1 Hz was achieved by virtue of feedback-loop-based intensity noise suppression. Based on systematic noise analysis and experimental investigation, we found that the pump noise and temperature-dependent noise of the fiber splitter and the photodetector contributed mainly to the RIN of the fiber amplifier. Therefore, we carefully designed a feedback-loop-based Yb-doped all-fiber amplifier, and finely stabilized the temperature of the pump diode, fiber splitters, and photodetectors. Consequently, the RIN can be suppressed down to −72.5 dBc/Hz around 1 mHz. This low-intensity all-fiber Yb-doped amplifier can be used for space-borne gravitational-wave detection.

Ni/Ga2O3 based Schottky diode temperature sensor

Temperature sensors are the integrated part of electronics used in most of the applications. Present work demonstrates the temperature sensor based on ultra-wide bandgap semiconducting material, i.e.,Ga2O3. The material is known for its wider bandgap and radiation hardness properties. Ni/Ga2O3 based Schottky barrier device is simulated for sensing the temperature in the current range of 100 µA to 0.1 µA and in temperature range from 200 K to 600 K using SILVACO Atlas software. Relevant models such as bandgap narrowing, Schokely-Read-Hall, etc. were employed to ensure accuracy in the results. The simulated current–voltage (I-V) plots showed exponential variation and followed ideal thermionic emission model. The I-V plots were used to find the thermal sensitivity of device under considerations, which showed linearity in the measured current range. The maximum sensitivity is estimated as 3.22 mV/K at measuring current level of 0.1 µA.

Experimental and numerical analysis of effect of combined drop-shape pin fins and plate fins type heat sink under natural convection

As the junction temperature of a light-emitting diode (LED) is inversely proportional to its lifespan and efficiency. This study investigates the thermal performance of heat sink-based model with a drop-shaped pin fin for LED cooling under natural convection, experimentally, and numerically. The study used three distinct drop form pin fin arrays with variable vertical fin spacing (Sv = 25, 50, and 75 mm), with the best array being used in subsequent studies with variations in drop-shaped pin fin size (diameter DD and apex length LD ). The heat transfer coefficient and Nusselt number were obtained in the quantitative analysis of thermal performance. A numerical model with Boussinesq approximation for natural convection is used for this study and well-validated with experimental results. A qualitative investigation was also carried out utilizing numerical research to investigate velocity streamlines and their impacts on heat transfer enhancement in various configurations. An experimental test with conventional plate fin, circular pin fins were done for the verification of the test setup results and their results were compared with results calculated from the standard correlations presented in previous well-known literature. The maximum heat transfer coefficient was found to be 12.80 W/m2K for drop form pin fins with vertical fin spacing (Sv ) equal to 75 mm, a diameter of 6 mm, and a length of 7.2 mm, and the corresponding Nusselt number was 94.85. Also, the maximum enhancement in Nusselt number was found to be (Nu/Nu plate fin) 3.11 corresponding to the conventional plate-fin heat sink. This comparison will help the industrialists determine innovative passive cooling technology for electronic devices such as LED street lights.

Моделирование процессов тепловой диагностики тепловозной выпрямительной установки

Purpose: To analyze the possibility of determining locomotive rectifier unit malfunction with the help of thermal fields and diode temperature measurement. Methods: There were applied the analysis of rectifier unit faults and their components for a certain period, modeling and thermal calculation in Solid Works Software Package. Results: The picture of thermal field and temperature changes at the diagnosis of regularly running diesel rectifier unit as well as at diode faults such as a breakdown and break. Practical significance: The possibility of monitoring the technical condition of a diesel locomotive rectifier unit when determining diode thermal fields as well as of determining possible malfunctions by diode temperature change is shown.

An Interface ASIC Design of MEMS Gyroscope with Analog Closed Loop Driving.

This paper introduces a digital interface application-specific integrated circuit (ASIC) for a micro-electromechanical systems (MEMS) vibratory gyroscope. The driving circuit of the interface ASIC uses an automatic gain circuit (AGC) module instead of a phase-locked loop to realize a self-excited vibration, which gives the gyroscope system good robustness. In order to realize the co-simulation of the mechanically sensitive structure and interface circuit of the gyroscope, the equivalent electrical model analysis and modeling of the mechanically sensitive structure of the gyro are carried out by Verilog-A. According to the design scheme of the MEMS gyroscope interface circuit, a system-level simulation model including mechanically sensitive structure and measurement and control circuit is established by SIMULINK. A digital-to-analog converter (ADC) is designed for the digital processing and temperature compensation of the angular velocity in the MEMS gyroscope digital circuit system. Using the positive and negative diode temperature characteristics, the function of the on-chip temperature sensor is realized, and the temperature compensation and zero bias correction are carried out simultaneously. The MEMS interface ASIC is designed using a standard 0.18 μM CMOS BCD process. The experimental results show that the signal-to-noise ratio (SNR) of sigma-delta (ΣΔ) ADC is 111.56 dB. The nonlinearity of the MEMS gyroscope system is 0.03% over the full-scale range.

The Estimated Temperature of the Semiconductor Diode Junction on the Basis of the Remote Thermographic Measurement.

The value of a semiconductor's diode temperature determines the correct operation of this element and its useful lifetime. One of the methods for determining the die temperature of a semiconductor diode is through the use of indirect thermographic measurements. The accuracy of the thermographic temperature measurement of the diode case depends on the prevailing conditions. The temperature of the mold body (the black part of the diode case made of epoxy resin) depends on the place of measurement. The temperature of the place above the die is closer to the die temperature than the temperature of mold body fragments above the base plate. In addition, the difficulty of its thermographic temperature measurement increases when the surface whose temperature is being measured is in motion. Then, the temperature measured by thermography may not apply to the warmest point in the case where the die temperature is determined. Information about the difference between temperatures of the different parts of the mold body and the die may be important. For this reason, it was decided to check how much the temperature measurement error of the die diode changes if the temperature of the diode case is not measured at the point that is above the die.