High-gain emitter inversion layer PNP vertical bipolartransistor in compensated CMOS technology

In this Letter, a novel vertical bipolar junction transistor (BJT) triggered silicon‐controlled rectifier (VBTSCR) is proposed for advanced nanoscale electrostatic discharge (ESD) protection applications. With the help of a vertical NPN transistor in floating base configuration, the new silicon‐controlled rectifier (SCR) structure achieves lower trigger voltage and better clamping capacity than the prior enhanced modified lateral SCR (EMLSCR) under the same layout footprint. The ESD characteristics are measured using the transmission line pulsing tester. Compared with that of EMLSCR, the trigger voltage of VBTSCR drops by 1 V, and the effective ESD robustness of VBTSCR has been doubled significantly. Based on these advantages, the proposed VBTSCR can provide ESD protection for the advanced 1.8/2.5 V input/output circuits more efficiently.

A self-aligned vertical Bipolar Charge Plasma Transistor (V-BCPT) with a buried metal layer between undoped silicon and buried oxide of the silicon-on-insulator substrate, is reported in this paper. Using two-dimensional device simulation, the electrical performance of the proposed device is evaluated in detail. Our simulation results demonstrate that the V-BCPT not only has very high current gain but also exhibits high BVCEO · fT product making it highly suitable for mixed signal high speed circuits. The proposed device structure is also suitable for realizing doping-less bipolar charge plasma transistor using compound semiconductors such as GaAs, SiC with low thermal budgets. The device is also immune to non-ideal current crowding effects cropping up at high current densities.

Minimizing the contact barriers at the interface, forming between two different two-dimensional metals and semiconductors, is essential for designing high-performance optoelectronic devices. In this work, we design different types of metal-semiconductor heterostructures by combining 2D metallic MX2 (M = Nb, Hf; X = S, Se) and 2D semiconductor SiH and investigate systematically their electronic properties and contact characteristics using first principles calculations. We find that all the MX2/SiH (M = Nb, Ta; X = S, Se) heterostructures are energetically stable, suggesting that they could potentially be synthesized in the future. Furthermore, the generation of the MX2/SiH metal-semiconductor heterostructures leads to the formation of the Schottky contact with ultra-low Schottky barriers of a few tens of meV. This finding suggests that all the 2D MX2 (M = Nb, Ta; X = S, Se) metals act as effective electrical contact 2D materials to contact with the SiH semiconductor, enabling electronic devices with high charge injection efficiency. Furthermore, the tunneling resistivity of all the MX2/SiH (M = Nb, Ta; X = S, Se) MSHs is low, confirming that they exhibit high electron injection efficiency. Our findings underscore fundamental insights for the design of high-performance multifunctional Schottky devices based on the metal-semiconductor MX2/SiH heterostructures with ultra-low contact barriers and high electron injection efficiency.

Most of the semiconductor device geometries that are being experimented with for improved magnetic field sensing do not lend themselves to accurate analytical modeling. The vectorial interaction taking place between the electrical current and the magnetic field complicates the problem of solving nonlinearly coupled carried density and electrostatic potential equations. In this work, solutions to the carrier density and electrostatic potential distributions are obtained by using a finite-element technique for a structure representing lateral and vertical bipolar transistors with multiple collectors. The results presented show the effect of the magnetic field to be very nonuniformly distributed around the emitter with a heavy-concentration near the emitter edges where the Lorentz-force-driven carriers are stopped at the insulating boundaries and give rise to a magnetoconcentration in the carrier densities. Distribution of currents collected by a multitude of collectors surrounding the emitter and their sensitivity to the magnetic field are given. The vertical magnetosensitivities are found to be an order of magnitude smaller than the lateral magnetosensitivity because of the lack of such a magnetoconcentration of carriers under the emitter. The computer program developed can simulate unipolar as well as bipolar magneto-sensitive devices with any boundary geometry.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A new dc measurement technique that allows a direct observation of the Early effects and the base push-out effect in vertical bipolar transistors is described. The technique uses a special test structure and may be used to accurately determine the forward and reverse Early voltages used in the Gummel Poon model. The improvements provided by this method over conventionally used parameter extraction techniques are demonstrated through measurements on silicon and through two-dimensional device simulations.

The silicon-based gate-controlled lateral bipolar junction transistor (BJT) is a controllable four-terminal photodetector with very high responsivity at low-light intensities. It is a hybrid device composed of a MOSFET, a lateral BJT, and a vertical BJT. Using sufficient gate bias to operate the MOS transistor in inversion mode, the photodetector allows for increasing the photocurrent gain by 106 at low light intensities when the base-emitter voltage is smaller than 0.4 V, and BJT is off. Two operation modes, with constant voltage bias between gate and emitter/source terminals and between gate and base/body terminals, allow for tuning the photoresponse from sublinear to slightly above linear, satisfying the application requirements for wide dynamic range, high-contrast, or linear imaging. MOSFETs from a standard 0.18-μm triple-well complementary-metal oxide semiconductor technology with a width to length ratio of 8 μm /2 μm and a total area of ~ 500 μm2 are used. When using this area, the responsivities are 16-20 kA/W.

A fabrication technique is described for the formation of metal-semiconductor contacts, with minimum contamination, on a production basis. Contacts of this type have been formed by cleavage in high vacuum in a stream of metal atoms which has very limited application or by normal evaporation which produces contaminated contacts. The basic structure consists of a layer of epitaxial silicon, on a suitable substrate, on which is deposited a film of molybdenum by the hydrogen reduction of the chloride in the same chamber. The system is adaptable to multiple slice operation. Measurements of switching speed indicate that the reverse recovery times are on the order of 1 nanosecond or less. This very short recovery time is attributed to the high injection efficiency which approaches unity. The high electron injection efficiency reduces the minority carrier concentration in the depletion region thereby reducing trr. Data is presented on both forward and reverse characteristics for diodes fabricated on both epitaxial and bulk silicon with different impurity concentrations. Reverse currents on the order of 10 nanoamps at 10 volts have been observed on epitaxial silicon and forward current densities of 30,000-40,000 amperes per square centimeter, at 1 volt, have also been observed. Data is also presented to show the effect of impurity concentration on barrier height.

The features of modern complementary bipolar technologies (CB-technologies) for analog applications have been analyzed and the main trends in their development are considered. Different industrial CBtechnologies are compared on the basis of two parameters of complementarity, namely the quality factor (βV A ) and Johnson’s parameter (BV CEO f T ). The p-epitaxial-planar CB-technology has been studied by the method of two-dimensional numerical simulation using the TCAD Sentaurus software for vertical n–p–n and p–n–p transistors. A careful calibration of the parameters of technological and electrophysical 2D models on the basis of test structures has shown sufficient accuracy of the used methodology for practice.

The static and dynamic performance of 600-V, n-channel, vertical insulated-gate bipolar transistors (IGBTs) at temperatures as low as 77 K has been measured and analyzed. The IGBTs demonstrate a better performance in turn-off times and maximum gate controllable current, at the expense of a slightly higher forward drop. It is shown that inherent in the IGBT is a parasitic thyristor that must be suppressed to retain gate-control operation. At 300 K, the dynamic latching current or maximum gate controllable current of the n-IGBT was 3.3 A, but it was current limiting at 5.4 A at both 195 and 77 K. Hence, by simply lowering the operating temperature, one can achieve the desirable current-limiting feature rather than encounter the often destructive latching behavior. >

In this contribution we present a novel simulation strategy for the electrothermal analysis of power multicellular transistors. The approach is based on the enhancement of a commercially available circuit simulator, namely Agilent Advanced Design System, and relies on an effective approach to describe the 3-D thermal process in both steady-state and transient conditions. A prototype of vertical power bipolar transistor has been considered as a case-study. The fairly good agreement between simulated and experimental results demonstrates that the proposed methodology can be successfully exploited for forecasting the electrothermal behavior of power transistors with complex layout, thus providing plain guidelines to improve their thermal ruggedness.

A Total Ionizing Dose (TID) study was performed on vertical NPN bipolar transistors used in two radiation hardened 10V and 40V BiCMOS processing technologies. The data shows increased total dose degradation with decreasing base doping concentration. Testing was performed at both high [90 rad(Si)/sec] and low [0.1 rad(Si)/sec] dose rates with minimal differences noted at the lower dose rate. The primary finding from this study was that, with proper device modeling and selection of device operating currents, these devices are suitable for 300 krad(Si) mixed signal applications.

This paper presents a wideband and low-noise direct conversion front-end receiver supporting VHF and UHFbands simultaneously. The receiver iscomposed of a low-noise amplifier (LNA), a down conversion quadrature mixer, and a frequency divider by 2. The cascode configuration with the resistor feedback is exploited in the LNA to achieve a wide operating bandwidth. Four gainstep modesare employed using a switched resistor bank and a capacitor bank in the signal path to cope with wide dynamic input power range. The verticalbipolar junction transistors are used as the switching elements in the mixer to reduce 1/f noise corner frequency. The proposed front-end receiver fabricated in 0.18 <TEX>${\mu}m$</TEX> CMOS technology shows very low minimum noise figureof 1.8 dB and third order input intercept pointof -12dBm inthe high-gain mode of 26.5 dBmeasured at 500 MHz.The proposed receiverconsumeslow current of 20 mA from a 1.8 V power supply.

Complete integration of optical laser sources and waveguides with electronics on a single semiconductor wafer has been a long sought after and elusive goal. Future development of optoelectronic integrated circuits (OEICs) hinges on the development of monolithically integrated laser/waveguide systems with low threshold currents and high injection efficiency into the passive waveguide. This paper reports progress in developing just such a high efficiency Transverse Junction Stripe1 (TJS) laser source integrated with an external passive waveguide suitable for optical interconnection applications. Threshold current as low as 60 mA and injection efficiencies as high as 40% are reported.

Nonuniformity impacting factors on an IRFPA with direct injection (DI) readout circuit and InSb PV detector are analyzed in this paper. The nonuniformity of threshold voltage results in deviation of detector bias and current. Then the detector nonuniformity and injection efficiency nonuniformity occur. Another expression for injection efficiency is deduced and its relation with detector bias is obtained. Relation between FPA nonuniformity and detector I-V characteristics is analyzed. The bias range from -0.2V to -0.1V is an ideal operating region for detector array. Small deviation of detector current, insensitive to nonuniformity of threshold voltage, uniform response of detector array, high detector impedance and high injection efficiency are all satisfied in this region. The best gate voltage range of injection MOSFET is from 3.6V to 3.7V. FPA has minimum nonuniformity in this region, which is corresponding to detector bias from -0.2V to -0.1V. Results shown in this paper optimize the performance of FPA.

The p-n tandem design of a sensitized solar cell is a novel concept holding the potential to overcome the efficiency limitation of conventional single-junction sensitized solar cells. Significant improvement of the photocurrent density (Jsc) of the p-type half-cell is a prerequisite for the realization of a highly efficient p-n tandem cell in the future. This study has demonstrated effective photocathodes based on novel organometal halide perovskite-sensitized mesoporous NiO in liquid-electrolyte-based p-type solar cells. An acceptably high Jsc up to 9.47 mA cm(-2) and efficiency up to 0.71% have been achieved on the basis of the CH3NH3PbI3/NiO solar cell at 100 mW cm(-2) light intensity, which are significantly higher than those of any previously reported liquid-electrolyte-based p-type solar cells based on sensitizers of organic dyes or inorganic quantum dots. The dense blocking layer made by spray pyrolysis of nickel acetylacetonate holds the key to determining the current flow direction of the solar cells. High hole injection efficiency at the perovskite/NiO interface and high hole collection efficiency through the mesoporous NiO network have been proved by time-resolved photoluminescence and transient photocurrent/photovoltage decay measurements. The limitation of these p-type solar cells primarily rests with the adverse light absorption by the NiO mesoporous film; the secondary limitation arises from the highly viscous ethyl acetate-based electrolyte, which is helpful for the solar cell stability but hinders fluent diffusion into the pore channels, giving rise to a nonlinear dependence of Jsc on the light intensity.