Measurement circuits for silicon-diode and solar-cell lifetime andsurface recombination velocity by electrical short-circuit current decay

Two improved switching circuits for transient electrical short-circuit decay are presented that allow more accurate determination of base-region minority-carrier lifetime and back-surface recombination velocity of silicon p-n junction solar cells and diodes. In one circuit, metal-oxide-semiconductor transistors replace the bipolar switching circuit used in the original implementation of the method as described by T.W. Jung, et al. (ibid., vol.ED-31, p.588, 1984). In the other circuit, a pulse generator directly excites the device under study. Comparison of the two circuits by illustrative measurements shows that, in comparison to the original implementation of the method, these versions allow measurement of shorter effective lifetimes, such as those characteristic of low-resistivity (about 0.1 Ω-cm) silicon solar cells     

All-Optical Comb Switch for Multiwavelength Message Routing in Silicon Photonic Networks

Simultaneous all-optical switching of 20 continuous-wave wavelength channels is achieved in a microring resonator-based silicon broadband 12 comb switch. Moreover, single-channel power penalty measurements are performed during active operation of the switch at both the through and the drop output ports. A statistical characterization of the drop-port insertion losses and extinction ratios of both ports shows broad spectral uniformity, and bit-error-rate measurements during passive operation indicate a negligible increase in signal degradation as the number of wavelength channels exiting the drop port are scaled from one to 16, with peak powers of 6 dBm per channel. A high-speed broadband switching device, such as the one described here, is a crucial element for the deployment of interconnection networks based on silicon photonic integrated circuits.     

Static and dynamic characterization of large-areahigh-current-density SiC Schottky diodes

The static and dynamic characteristics of large-area, high-voltage 4H-SiC Schottky barrier diodes are presented. With a breakdown voltage greater than 1200 V and a forward current in excess of 6 A at 2 V forward bias, these devices enable for the first time the evaluation of SiC Schottky diodes in practical switching circuits. These diodes were inserted into standard test circuits and compared to commercially available silicon devices, the results of which are reported here. Substituting SiC Schottky diodes in place of comparably rated silicon PIN diodes reduced the switching losses by a factor of four, and virtually eliminated the reverse recovery transient. These results are even more dramatic at elevated temperatures. While the switching loss in silicon diodes increases dramatically with temperature, the SiC devices remain essentially unchanged. The data presented here clearly demonstrates the distinct advantages offered by SiC Schottky rectifiers, and their emerging potential to replace silicon PIN diodes in power switching applications     

A novel circuit for accurate characterization and modeling of thereverse recovery of high-power high-speed rectifiers

As circuit switching frequency continues to increase, there is a need to produce faster rectifiers with lower power losses. Efficient utilization of high-power ultrafast rectifiers requires precise knowledge of the key static and dynamic switching parameters, especially the reverse-recovery characteristics. Conventional reverse-recovery test circuits were developed to test rectifiers with reverse-recovery times (t_RR) greater than 100 ns, however, new measurement techniques are needed for accurate characterization and modeling of the high-power ultrafast rectifier reverse-recovery process. A test circuit topology is proposed which offers several advantages over existing test circuits. This circuit offers the ability to characterize high-power ultrafast rectifiers at very high di/dt and also provides independent control of bias current, reverse voltage and di/dt. This circuit is also studied using a two-dimensional (2-D) mixed device and circuit simulator in which the device under test is represented as a 2-D finite-element grid and the semiconductor equations are solved under boundary conditions imposed by the proposed test circuit. This simulation tool is used to understand the device physics of the reverse-recovery process and develop more accurate models to be implemented in behavioral circuit simulators. The simulation results are then compared to the measured data for a silicon P-i-N and 200-V GaAs Schottky rectifier under various measurement conditions. Simulation results are shown to be in excellent agreement with the measured data     

Performance evaluation of high-power GaAs Schottky and siliconp-i-n rectifiers in hard- and soft-switching applications

The dynamic switching characteristics of high-power GaAs Schottky and silicon p-i-n rectifiers are studied at various temperatures. Devices were first characterized to measure forward and reverse I-V, C-V, reverse breakdown voltage, and reverse-recovery performance. The same devices were characterized for turn on and turn off in switching circuits designed to study the dynamic switching performances under hard- and soft-switching conditions at different temperatures. Advanced two-dimensional (2-D) mixed device and circuit simulations were used to study the internal plasma dynamics under boundary conditions imposed by the circuit operation. It is shown that for hard-switching applications, GaAs Schottky power rectifiers exhibit significantly reduced switching power losses compared to silicon p-i-n rectifiers. For soft-switching applications, there is not a significant difference in the switching power losses for these two devices. Diode performance at elevated temperatures is measured and simulated, and temperature dependencies of switching and conduction power losses are analyzed     

Behavioral EMI models of complex digital VLSI circuits

Increasing EMI potential of high-performance digital circuits like 32bit microcontrollers demand for switching current models and feasible ways to run netlist-based EMI simulations. A promising modeling approach for digital VLSI circuits is presented and a silicon test vehicle for correlation between models and measurements is described.     

Inductive switching of 4H-SiC gate turn-off thyristors

The high-temperature operation of a silicon carbide gate turn-off thyristor is evaluated for use in inductively loaded switching circuits. Compared to purely resistive load elements, inductive loads subject the switching device to higher internal power dissipation. The ability of silicon carbide components to operate at elevated temperatures and high power dissipations are important factors for their use in future power conversion/control systems. In this work, a maximum current density of 540 A/cm² at 600 V was switched at a frequency of 2 kHz and at several case temperatures up to 150°C. The turn-off and turn-on characteristics of the thyristor are discussed     

Gallium arsenide Schottky power rectifiers

This paper discusses the development of high-performance gallium arsenide Schottky rectifiers for power switching applications. These diodes are shown to exhibit superior turn-on and turn-off dynamic switching characteristics when compared with silicon p-i-n rectifiers. The theoretical analysis presented in the paper indicates that the gallium arsenide Schottky power rectifier will be attractive for high-frequency power switching circuits operating at 1.00-300 V.     

A switching lateral transistor

A switching phenomenon has been reported in certain lateral geometry transistors in silicon integrated circuits. These devices switch between conducting and nonconducting states at a critical value of VCE. A hypothesis for the mechanism has been proposed. In this paper an equivalent circuit is developed for the switching lateral transistor and is used to predict transistor behavior. The effect of manufacturing tolerances on the device switching voltage is investigated and a technique of production control is proposed. Circuits using the device are described in which the circuit switching voltage may be varied over a wide range. Some applications of the switching lateral transistor, as an overvoltage protection circuit and a relaxation oscillator, are described.     

Switching noise picked up by a planar dipole antenna mounted nearintegrated circuits

For applications in which antennas are located near or in integrated circuits (ICs), the switching noise from digital circuits can interfere with the operation of antennas. This paper presents a study of the switching noise picked up by a planar dipole antenna from a divide-by-128 IC located near the antenna. To develop understanding of the measurement results, a lumped-element simulation model has been developed. Quantitative agreements between the measurements and simulations for numerous experiments have been obtained. The measurements indicate that by selecting the signal frequency on the antennas much greater than the circuit frequency, the immunity from switching noise can be improved. The measurements also showed that circuits such as buffers are relatively noisier, and emanate more noise at higher operating frequencies. Finally, the measurements showed that using antennas with a differential or balanced feed structure can substantially reduce the coupling of switching noise (~20 dB) which is mostly common-mode in nature     

Low power design of a field sequential color LCoS chip

The low power design of a field sequential color （FSC） liquid crystal on silicon （LCoS） chip for near-to-eye application is presented in this paper. Dual power supplies are used in the design, that is, the supply for part of driving circuits is 3.3 V, and the one for the active matrix is 5.0 V. Serial-to-parallel conversion circuits are adopted to lower the pixel clock frequency of the chip. Also, an idle state is inserted into the pixel clock signal to decrease the switching activity factor to further reduce the power consumption. The LCoS chip is fabricated with 0.35 μm CMOS process and its power consumption is only about 300 mW.     

Integrated micromechanical sensors and actuators in silicon

The integrated silicon microsensor and microactuator field is a rapidly developing branch of the microelectronic technology research. The vast potential of these sensors lies in the compatibility with conventional microelectronic circuits in silicon. Special efforts are often required to maintain this fundamental material compatibility, while enabling the fabrication of versatile sensors and actuators. Sensors in silicon are possible for the measurement of many different non-electrical quantities. This overview is focussed on micromechanical sensors and actuators. The basic technologies used for the fabrication of micromechanical structures in silicon are presented with a special emphasis on their compatibility with integrated electronic readout circuits. The performance and the limitations are outlined using several successfully-fabricated integrated sensor and actuator structures.     

硅高压功率JFET开关性能

本文介绍一种垂直沟道结型场效应晶体管.给出器件的电参数、线性区等效电路、开关参数的测试电路及一些测试结果.对器件的开关参数进行了初步分析与计算.指出,器件的通态电阻R_(on)是涉及本器件开关性能的一个重要参数.最后,给出一例高速脉冲放大器的实际电路.     

Integrated circuit design for physical unclonable function using differential amplifiers

A physical unclonable function (PUF) based on process variations on silicon wafers is a very promising technology which finds various applications in identification and authentication, but only a few integrated circuits have been reported so far. As those circuits are vulnerable to power supply noises, switching noises and environmental variations, they lead to a reliability issue such as time-varying or metastable responses. To resolve this issue, this letter proposes a new integrated circuit design for PUFs using differential amplifiers. The feasibility of the proposed circuit has been theoretically analyzed and validated through HSPICE simulations for the previous and proposed circuits.     

Flip-Chip-Assembled Air-Suspended Inductors

This paper discusses high-performance planar suspended inductors for hybrid integration with microwave circuits. The inductors are fabricated using a silicon surface micromachining foundry process and assembled using flip-chip bonding. The silicon substrate is removed, leaving a metal inductor suspended 60 mum above the microwave substrate, thus reducing the parasitic capacitance and loss. Various rectangular, octagonal, and circular inductor geometries with one to five windings are designed with inductance values between 0.65 and 16 nH to demonstrate the flexibility of this technique. Measured self-resonant frequencies are between 5 and 34.8 GHz, with quality factors from 45 to 100. Equivalent circuits extracted from measurement for each inductor type show good agreement with measured impedance and full-wave simulations over frequency. The dc current handling limit is 200 mA     

Characteristics of a high-current, high-voltage Shockley diode

This paper describes design, development, characterization, and operation of a two-terminal, high-current, high-voltage silicon four-layer diode. The main feature of this new four-layer diode is a voltage-current characteristic which is, prior to switching, similar to that of an avalanche diode. This property is achieved by short-circuiting one emitter-base junction, resulting in a grid-type emitter geometry. The short-circuiting takes place over the entire device area in order to maintain uniform turn-on and uniform current conduction. Devices switching at 1000 volts or higher, with peak pulse current capability of 1000 amperes or more, are described. To achieve very high switching voltages, the stacking of two or three silicon chips was found to be useful. Extended tests Were performed at various combinations of pulsewidths (0.5 to 12 µs), repetition rates (0.2 to 2000 pulses per second), and operating times (0.1 to 2500 hours). The test circuits and the resulting turn-on and recovery times are summarized, Failure analysis establishes hot spot development or thermal fatigue as possible failure mechanisms. Since series operation of many devices is possible without complicated dividing networks, the complexity of pulse modulator circuitry is reduced, and resonantly charged circuits can exhibit a high degree of operation reliability and temperature insensitivity.     

A solid-state instrument for the measurement of frequency and phase angle in power systems

This paper describes the development of an instrument, using electronic switching circuits for the measurement of frequency and phase angles in power systems. The phase angle and frequency are indicated on a meter with linear scale. The instrument responds to changes in system frequency and the phase-angle measurement is inherently lead-lag sensitive.     

A BIST TPG for Low Power Dissipation and High Fault Coverage

This paper presents a low hardware overhead test pattern generator (TPG) for scan-based built-in self-test (BIST) that can reduce switching activity in circuits under test (CUTs) during BIST and also achieve very high fault coverage with reasonable lengths of test sequences. The proposed BIST TPG decreases transitions that occur at scan inputs during scan shift operations and hence reduces switching activity in the CUT. The proposed BIST is comprised of two TPGs: LT-RTPG and 3-weight WRBIST. Test patterns generated by the LT-RTPG detect easy-to-detect faults and test patterns generated by the 3-weight WRBIST detect faults that remain undetected after LT-RTPG patterns are applied. The proposed BIST TPG does not require modification of mission logics, which can lead to performance degradation. Experimental results for ISCAS'89 benchmark circuits demonstrate that the proposed BIST can significantly reduce switching activity during BIST while achieving 100% fault coverage for all ISCAS'89 benchmark circuits. Larger reduction in switching activity is achieved in large circuits. Experimental results also show that the proposed BIST can be implemented with low area overhead.     

High-power robust semiconductor electronics technologies in the new millennium

This paper presents an overview of power semiconductor devices for the development of advanced robust high-performance power electronic systems for the new millennium. Material and device technologies on silicon and wide energy band-gap semiconductors are discussed along with switching circuits and topologies. Short-term and long-term reliability issues of power semiconductor devices are discussed. An approach is presented to correlate converter field failures to dynamic switching stresses, residual defects and contaminants left in the semiconductor power switch, packaging, and thermal management. Component and system level simulation, modeling and CAD requirements are evaluated. System-level optimization is proposed as an essential requirement to develop robust power systems at affordable cost.     

Femtojoule high speed planar GaAs E-JFET logic

An integrated inverter stage operating in the gigabit range at a static power dissipation of 100 µW was built for future use in LSI logic circuits. Planar gallium arsenide technology was employed using selective ion-implanted enhancement mode junction field-effect transistors (E-JFET) having 3-µm gate lengths. A nine-stage ring oscillator served as a test vehicle to assess the speed-power product for digital applications. A theoretical analysis shows the transistor operates during the switching transient in the saturation regime, notwithstanding steady-state operation in the linear regime. When the transistor is switched off, the transient response is governed by the load resistance and the input capacitance of the subsequent stage. Means of reducing the switching time by increasing the supply voltage, nonlinear load devices, an output buffer stage, and reduction of gate length and width are described. Directly coupled E-JFET logic does not require level shifting, and, therefore, offers advantages over depletion-mode gallium arsenide MESFET logic by reducing the number of circuit elements per gate. Projected gallium arsenide E-JFET LSI logic circuits will surpass silicon-based bipolar logic with respect to both speed and power, and n-channel silicon MOS logic with respect to speed.