Carrier Injection Effect Research Articles

Photonics Rib Waveguide Dimension Dependent Charge Distribution and Loss Characterization

The simulation of behaviour of the charge distribution and the loss characteristic for rib-waveguide is demonstrated by using silicon-on-insulator (SOI). In this simulation, the rib waveguide is designed at a core width of 450nm, core height of 250nm, rib height of 50nm and buried oxide height of 100nm. These dimensions are set as reference. The aspiration of designing rib waveguide instead of other type of waveguide such as ridge waveguide is from the higher light confinement that can be accomplished by rib waveguide as the refractive index difference is huge and the designing of an active device can be realized. In this analysis, free carrier-injection effect was implemented in the first part of the simulation to study the distribution charges of rib-based waveguide structure based on basic dimensions. In this analysis, electrical voltage was varied from 0V to 1.2V in steps of 0.2V for the analysis of distribution of electron. In the second part of the simulation, four design parameters had been amended which included the core width and height, rib height and buried oxide height. Physical dimensions of the waveguide were altered to achieve smaller device footprint with optimized performance affecting large Free Spectral Range (FSR) and high Q-factor. With proper waveguide physical dimensions design, a good performance Micro-Ring Resonator (MRR) exhibits the principles of wide FSR and Q-factor can be achieved.

Modelling and Failure Analysis of SiC MOSFET under the Effects of Parasitic Parameters

Recent years, SiC MOSFET has been gradually utilized in high power devices. However, it has become one of the highest failure rate devices in circuit systems. Its failure relates to the degradation which caused by the hot carrier injection(HCI) effect. Because the parasitic parameters make the oscillations in switching processes more intense, the switching time and voltage overshoot increases, and thus HCI effect exacerbates. So, it is necessary to analyse the influence of parasitic parameters on the failure of SiC MOSFET. In this paper, an improved SiC MOSFET model with all key parasitic parameters is built to set up an accurate test circuit. The parasitic parameters were divided into four parts: body diode, parasitic resistance, parasitic capacitance and parasitic inductance. According to the simulation, it concluded that only the parasitic inductance has a great impact on the HCI effect and the impacts are different according to the different locations of parasitic inductance. The influence of the parasitic inductance on the load circuit and near the source is much greater than other parts. Their increase greatly increases switching time and voltage overshoot, and thus exacerbates HCI effect and accelerates the degradation of SiC MOSFET.

Aging in CMOS RF Linear Power Amplifiers: An Experimental Study

An extensive experimental analysis of the hot carrier injection (HCI) and bias temperature instability (BTI) aging effects on RF linear power amplifiers (PAs) is presented in this article. Two different 2.45-GHz PA topologies have been implemented in a CMOS 65-nm technology: one based on a classical common-source (CS) and choke inductor and another one based on a complementary current-reuse (CR) circuit, both of them producing similar gain and output 1-dB compression point (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1dB</sub> ). These circuits have been stressed to produce accelerated aging degradation, by applying increasing supply (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DD</sub> ) voltages or increasing RF input powers (PIN). The degradation on the transistor parameters (threshold voltage and mobility), dc bias point (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dc</sub> current), and RF performance (gain, matching, and compression point) has been simultaneously measured. This has allowed us to observe how the reduced transistor degradation in CR PA results in higher robustness in its RF parameters compared with the CS PA circuit. The equivalent root-mean-square (rms) voltages have been proposed as an observable metric to assess the combined dc + RF stress in a PA circuit. This has been applied to a semianalytical model, providing comprehension of the link between the conditions under which a circuit is operated, the degradation of the transistor parameters, and the effects on the dc current and RF performance.

The influence of total ionizing dose on the hot carrier injection of 22 nm bulk nFinFET

We investigate the hot carrier injection effect (HCI) and how X-ray radiation impacts the HCI of 22-nm nFinFETs as a function of device geometry and irradiation bias conditions in this paper. In the HCI test, the degradation of threshold voltage and saturation current decreases with the increase of fin number, which means that HCI weakens when the fin number increases. The reason is attributed to the coupling effect between fins. Moreover, irradiation is shown to weaken the degradation during the subsequent hot carrier test. The influence of irradiation on HCI is more obvious with ON bias than that of OFF bias and transmission gate bias. It is supposed that the Si–H bonds can be broken by irradiation before the HCI test, which is one reason for the irradiation influence on HCI. Besides, trapped charges are generated in the shallow trench isolation by the radiation, which could reduce the channel electric field, and then weaken the HCI.

First principles calculation of metal (Ni and Cu) contact on the electronic transport properties of 2D GeP semiconductor

Two-dimensional (2D) IV-V semiconductors are shown to possess suitable bandgap, strongly anisotropic electronic and optical properties for nanoelectronic and optoelectronic applications. Motivated by the experimental demonstration of the 2D IV-V semiconductors, we have computationally designed the monolayered GeP nanodevice consisting of nickel (Ni) and copper (Cu) metal contacts, and evaluated their transport properties. Using first principles calculations combined with non-equilibrium Green’s function, we have calculated the current density (J) versus bias (Vb), and the transmission coefficient. Both Ni and Cu metals could form excellent metallization contact with the GeP semiconductor channel, leading to effective carrier injection to the semiconductor and yielding significant improvements on the transport properties. The current is determined by the potential difference at the interface and the left/right electrode density of states (L/RDOS) coupling of the device. These two factors play predominant role at low and moderate biases, respectively. Our simulations have shown that the 2D GeP electronic device could be significantly improved by appropriate metal contact, which can be helpful to the 2D IV-V semiconductors for future electronic applications.

Two-dimensional tin perovskite nanoplate for pure red light-emitting diodes

Halide perovskites are rising as promising luminescent materials for display applications for their sharp emission peaks and high luminescence quantum yield. However, the heavy metal character of lead is one concern that shadows its application. In this work, monolayer Ruddlesden–Popper 2D structural tin perovskite (PEA)2SnI4 (PEA = C8H9NH3+) is explored for a pure red color light emitting diode (LED). The manipulation of crystal growth kinetics enables the formation of highly ordered nanoplates, bringing high luminescence yield approaching 10% with an emission peak at 630 nm. Meanwhile, the highly oriented and ordered nanoplates structure allows effective carrier injection. The LED shows a low turn on voltage of 2.2 V, an external quantum efficiency of 0.52% and a max luminance of 355 cd m−2. The luminescence quantum yield is comparable to the best performing device based on lead perovskites in the pure red emission region. This work provides a strategy to explore 2D structures for efficient macroscale LEDs.

Research for Hot Carrier Degradation in N-Type Bulk FinFETs

In this paper, the effect of hot carrier injection on an n-bulk fin field-effect transistor (FinFET) is analyzed. The hot carrier injection method is applied to determine the performance change after injection in two ways, channel hot electron (CHE) and drain avalanche hot carrier (DAHC), which have the greatest effect at room temperature. The optimum condition for CHE injection is VG=VD, and the optimal condition for DAHC injection can be indirectly confirmed by measuring the peak value of the substrate current. Deterioration by DAHC injection affects not only hot electrons formed by impact ionization, but also hot holes, which has a greater impact on reliability than CHE. Further, we test the amount of drain voltage that can be withstood, and extracted the lifetime of the device. Under CHE injection conditions, the drain voltage was able to maintain a lifetime of more than 10 years at a maximum of 1.25 V, while DAHC was able to achieve a lifetime exceeding 10 years at a 1.05-V drain voltage, which is 0.2 V lower than that of CHE injection conditions.

Investigation of effects of charge injection and intrinsic ionic carriers in low-density polyethylene and cross-linked polyethylene

The effects of charge carrier injection and intrinsic ionic carriers on the conduction process in superclean low-density polyethylene and cross-linked polyethylene (LDPE and XLPE) and the associated development of space charge are investigated. The carrier mobility is measured directly by space charge measurements in a double- and triple-layer structure. It is shown that the difference between superclean LDPE and XLPE in the field-dependence of the current density results from the dominance of ions in XLPE introduced by cross-linking as compared to injected carriers in the case of superclean LDPE.

Total-ionizing-dose induced enhanced hot-carrier injection effect in the 130 nm partially depleted SOI I/O nMOSFETs

An enhanced threshold shift was observed in irradiated (total-ionizing-dose) 130 nm partially depleted silicon-on-insulator I/O nMOSFETs after 3000 s channel hot-carrier stress. This phenomenon was caused by the irradiation-induced additional channel lucky electrons which were injected in the silicon dioxide layers (STI/BOX/gate oxide). Mechanism of formation of greater substrate current in irradiated narrow devices was discussed. Accordingly, a model (enhanced lucky-electron model/Hot carrier injection effect) applied to devices in radiation space environment is established. In addition, the unusual phenomenon in irradiated devices with wide channel was also discussed.

Device Reliability Challenges in Advanced FinFET Technology

Abstract This article discusses the effect of hot carrier injection, bias temperature instability, and time-dependent dielectric breakdown on FinFET performance and reliability.

MOVPE-grown AlGaN-based tunnel heterojunctions enabling fully transparent UVC LEDs

We report on AlGaN-based tunnel heterojunctions grown by metalorganic vapor phase epitaxy enabling fully transparent UVC LEDs by eliminating the absorbing p-AlGaN and p-GaN layers. Furthermore, the electrical characteristics can be improved by exploiting the higher conductivity of n-AlGaN layers as well as a lower resistance of n-contacts. UVC LEDs with AlGaN:Mg/AlGaN:Si tunnel junctions exhibiting single peak emission at 268 nm have been realized, demonstrating effective carrier injection into the AlGaN multiple quantum well active region. The incorporation of a low band gap interlayer enables effective tunneling and strong voltage reduction. Therefore, the interlayer thickness is systematically varied. Tunnel heterojunction LEDs with an 8 nm thick GaN interlayer exhibit continuous-wave emission powers >3 mW near thermal rollover. External quantum efficiencies of 1.4% at a DC current of 5 mA and operating voltages of 20 V are measured on-wafer. Laterally homogeneous emission is demonstrated by UV-sensitive electroluminescence microscopy images. The complete UVC LED heterostructure is grown in a single epitaxy process including in situ activation of the magnesium acceptors.

A study on effects of total ionizing dose on hot carrier effect of PD I/O SOI PMOSFETs

Abstract The hot carrier injection (HCI) effect induced degradation is investigated for gamma ray irradiated PD I/O SOI PMOSFETs with T-shaped gate and H-shaped gate. Radiation enhanced effect on degradation during hot carrier stress is observed in two kinds of samples. And it is observed that radiation has more significant effect on T-gate devices than H-gate during stress time. Besides, the change on gate current degradation induced by irradiation is also worth noticing.

SAE ARP6338: Process for Assessment and Mitigation of Aging and Potential Early Wearout of Life-Limited Microcircuits (LLM)

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;This paper describes a Reliability Physics Analysis process to assess aging and the potential for early wearout of microcircuits, as documented in SAE ARP6338. As microcircuit feature sizes (gate length, line width, etc.) continue to shrink to near atomic levels, they become increasingly susceptible to aging mechanisms such as Electromigration, Time-Dependent Dielectric Breakdown, Hot Carrier Injection and Bias Temperature Instability effects. These mechanisms are driven by voltage, current and thermal operating stresses resulting in shorter times for aging to progress to the point where wearout can occur. If the times to wearout are shorter than the required lifetimes of the microcircuits in their applications, the microcircuits are called Life-Limited Microcircuits. A brief overview of these aging mechanisms and their impact on the long-life electronics systems used in Aerospace, Automotive, Defense, and other High Performance industries is provided. A summary of the SAE ARP6338 approach and implementation recommendations is also provided along with its importance to automotive Advanced Driver-Assistance Systems and autonomous electronic systems.&lt;/div&gt;&lt;/div&gt;

Highly efficient and foldable top-emission organic light-emitting diodes based on Ag-nanoparticles modified graphite electrode

Abstract Top-emission flexible organic light-emitting devices (TE-FOLEDs) are highly suitable for next generation display due to their numerous assets including top-emitting configuration and mechanical flexibility. One major challenge in TE-FOLEDs is to prepare a deformable and reflective bottom electrode capable of effective carrier injection. In this paper, a new strategy for efficient and foldable TE-FOLEDs is demonstrated. It is based on a highly conductive Ag-nanoparticles (Ag-NPs) modified graphite that is used as a flexible bottom electrode. The good reflectance to full-color emission (>59% over the whole visible wavelength range), ultralow sheet resistance (

Effect of hot carrier stress on device junctions measured by electron holography and scanning capacitance microscopy

The effect of hot carrier injection on the FET's junction properties has been investigated for CMOS NFET devices. Junction profiles and carrier concentration of stressed and unstressed devices are measured and compared by dual lens electron holography and scanning capacitance microscopy, respectively. The measurements reveal that the width of the junction on the drain side of the device that undergoes hot carrier stressing decreases, indicating a reduction in active carrier concentration. These results are consistent with the hypothesis of phosphorous dopant passivation by the hot carrier induced release of hydrogen into the drain side extension region.

Role of ITO ultra-thin layer in improving electrical performance and thermal reliability of Au/ITO/Si/Au structure: An experimental investigation

In this paper, the role of introducing an intermediate Indium Tin Oxide (ITO) thin-film in improving the Au/Si Schottky Barrier Diodes (SBDs) electrical performance is experimentally analyzed. The Au/ITO/Si/Au structures with different ITO thicknesses were fabricated using RF magnetron sputtering technique. The current-voltage (I-V) characteristics of the investigated structures are analyzed, where the device electrical parameters are extracted. It is found that the introduced ITO thin-film has a significant impact in reducing the ideality factor (n=1.25), the interfacial defects (Nss=1.5×1012 eV−1cm−2) and the series resistance (Rs=32Ω). Our study demonstrates that the use of ITO intermediate thin-film can generate minority carrier injection effects, which lead to achieve the dual role of enhanced derived current and lower series resistance. Moreover, the structure thermal stability behavior is investigated and compared with those of the conventional design in order to reveal the device reliability against the thermal variation. Furthermore, the effect of the annealing on the device thermal stability is also analyzed. Our investigation shows that the annealed structure provides the possibility for avoiding the degradation related-heating effects. Therefore, the proposed Au/ITO/Si/Au structure offers the opportunity for bridging the gap between achieving superior electrical performance and enhanced thermal stability. The obtained results may facilitate the design of high-performance SBDs for sensing and microelectronic applications.

Experimental Verification of the Effect of Photo-Excited Carrier Injection at Organic/Semiconductor Interfaces on Terahertz Wave Modulation

Experimental Verification of the Effect of Photo-Excited Carrier Injection at Organic/Semiconductor Interfaces on Terahertz Wave Modulation

Efficient blue and green phosphorescent OLEDs with host material containing electronically isolated carbazolyl fragments

Dry process-able host materials are well suited to realize high performance phosphorescent organic light-emitting diodes (OLED) with precise deposition of organic layers. We demonstrate in this study high efficiency green and blue phosphorescent OLED devices by employing 3-[bis(9-ethylcarbazol-3-yl)methyl]-9-hexylcarbazole based host material. By doping a typical green emitter of fac tris(2-phenylpyridine)iridium (Ir (ppy)3) in the compound the resultant dry-processed green device exhibited superior performance with low turn on voltage of 3.0 V and with peak efficiencies of 11.4%, 39.9 cd/A and 41.8 lm/W. When blue emitter of bis [2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium (III) was used, the resultant blue device showed turn on voltage of 2.9 V and peak efficiencies of 9.4%, 21.4 cd/A and 21.7 lm/W. The high efficiencies may be attributed to the host possessing high triplet energy level, effective host-to-guest energy transfer and effective carrier injection balance.

Unique reliability characteristics of fully depleted silicon-on-insulator tunneling FET

This study investigated the unique reliability characteristics of tunneling field effect transistors (TFETs) by comparing the effects of positive bias temperature instability (PBTI) and hot carrier injection (HCI) stresses. In case of hot carrier injection (HCI) stress, the interface trap generation near a p/n+ region was the primary degradation mechanism. However, strong recovery after a high-pressure hydrogen annealing and weak degradation at low temperature indicates that the degradation mechanism of TFET under the HCI stress is different from the high-energy carrier stress induced permanent defect generation mechanism observed in MOSFETs. Further study is necessary to identify the exact location and defect species causing TFET degradation; however, a significant difference is evident between the dominant reliability mechanism of TFET and MOSFET.

Tuning parametric processes in semiconductor diode lasers

We present GaAs/AlGaAs semiconductor lasers in which second-order nonlinearities are phase matched for efficient second-order nonlinear conversion. A comprehensive study of difference frequency generation (DFG) is presented, and the process is characterized for tuning, efficiency, and tolerances. External nonlinear conversion efficiency of 1.84×10−2%/W/cm2 is measured for the DFG process. The effects of carrier injection and temperature variation on DFG wavelength are studied, and the two effects are deconvolved for better understanding of carrier effects on nonlinear conversion. A wide DFG tuning range for the device operation is experimentally demonstrated where the idler wavelength can be tuned more than 30 nm for every 1-nm span of the pump wavelength.