Generation-recombination Noise Research Articles

Impact of interface traps and noise analysis on dual material graded channel CGAA FET: A device reliability

This paper explores the effects of changing the device's parameters, such as the gate length (Lg), nanowire radius (r), oxide thickness (tox), and frequency (f), on the noise characteristics of dual material graded channel (DMGC) cylindrical gate all around (CGAA) FET while considering the presence and absence of interface trap charges. The performance analysis of the DMGC CGAA FET with that of the SMGC (single material graded channel) CGAA FET, is carried out while taking into account the impact of trap charges. It's noteworthy that the DMGC FET demonstrates significant advantages, with improvement in Ion/Ioff, reduction in DIBL, and SS when compared to the SMGC CGAA FET, both in the cases of without and with traps. The investigation also extends to analyse the analog/RF performance of the DMGC FET, for different type of trap charges. Furthermore, the power spectral densities of current noise (Sid) and voltage noise (Svg) are examined by varying the device dimensions and temperature. This also addresses the various sources of noise, including flicker noise (1/f), generation-recombination (G-R) noise, and diffusion noise. These types of noise have different prevalence depending on the operating frequency. At low frequencies, flicker and G-R noises dominate, while at higher frequencies, diffusion noise becomes the prominent factor impacting the device's performance. The research findings indicate that the optimal performance of the DMGC CGAA FET is achieved with smaller nanowire radius and thinner oxide thickness, regardless of trap charges. These findings offer valuable insights for improving the design and performance of DMGC CGAA FET in low power applications.

Analysis of noise behavior and reliability of pocket doped negative capacitance FET under the impact of trap charges and temperature

This paper represents an in-depth investigation of low to high frequency noise performance of highly doped double pocket double gate NCFET (HDDP-DG-NCFET) and single gate NCFET (SG-NCFET) in the existence of Uniform and Gaussian trap charges at various frequencies and temperatures (200 K–400 K). The drain current noise spectral density (Sid) and Gate voltage noise spectral density (Svg) at different frequencies in existence of both type of trap charges are explored. In addition, the Sid as a function of frequency for various ferroelectric thicknesses (Tfe) is examined in the existence of Uniform trap charges. The findings show that, at lower frequencies flicker noise dominates, while at higher frequencies, the dominant noise element is diffusion noise. For the whole range of considered frequencies, the Generation-Recombination (G-R) noise is more substantial in existence of trap charges. It has been found that, the net Sid value of the HDDP-DG-NCFET for Uniform and Gaussian types of trap distribution is 6.98 × 10−14A2/Hz and 6.17 × 10−14A2/Hz, respectively. Moreover, the examination of Sid for various Tfe in presence of traps illustrates the significance of the ferroelectric layer in obtaining lower value of net Sid, particularly in the higher frequency region and the minimal net Sid value for Tfe = 7 nm as compared to other Tfe values. Finally, to examine the device's reliability, the temperature investigation for the noise in the non-existence and existence of trap charges demonstrates that, the impact of an increase in noise caused by the existence of trap charges is much pronounced at lower temperatures and smaller gate voltages, where G-R noise is observed to be the dominant noise component.

Quasiparticle Generation-Recombination Noise in the Limit of Low Detector Volume

We have measured the quasiparticle generation-recombination (GR) noise in aluminium lumped element kinetic inductors with a wide range of detector volumes at various temperatures. The basic detector consists of meandering inductor and interdigitated capacitor fingers. The inductor volume is varied from 2 to 153 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu \mathrm{m}^{3}$</tex-math></inline-formula> by changing the inductor width and length to maintain a constant inductance. We started with measuring the power spectrum density (PSD) of the detectors frequency noise which is a function of GR noise and we clearly observed the spectrum roll off at 10 kHz which corresponds to the quasiparticle lifetime. Using data from a temperature sweep of the resonator frequency we convert the frequency fluctuation to quasiparticle fluctuation and observe its strong dependence on detector volume: detectors with smaller volume display less quasiparticle noise amplitude. Meanwhile we observe a saturated quasiparticle density at low temperature from all detectors as the quasiparticle life time <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{\tau _{qp}}$</tex-math></inline-formula> approaches a constant value at low temperature.

Noise Optimization for MKIDs With Different Design Geometries and Material Selections

The separation and optimization of noise components is critical to microwave-kinetic inductance detector (MKID) development. We analyze the effect of several changes to the lumped-element inductor and interdigitated capacitor geometry on the noise performance of a series of MKIDs intended for millimeter-wavelength experiments. We extract the contributions from two-level system noise in the dielectric layer, the generation-recombination noise intrinsic to the superconducting thin-film, and system white noise from each detector noise power spectrum and characterize how these noise components depend on detector geometry, material, and measurement conditions such as driving power and temperature. We observe a reduction in the amplitude of two-level system noise with both an elevated sample temperature and an increased gap between the fingers within the interdigitated capacitors for both aluminum and niobium detectors. We also verify the expected reduction of the generation-recombination noise and associated quasiparticle lifetime with reduced inductor volume. This study also iterates over different materials, including aluminum, niobium, and aluminum manganese, and compares the results with an underlying physical model.

Study on low-frequency noise characteristics of hydrogen-terminated diamond FETs

In this work, the low frequency noise (LFN) characteristics of Hydrogen-terminated diamond FETs are investigated. Both generation-recombination (GR) noise and flicker noise (1/f noise) are found to contribute to the LFN spectrum. The characteristic frequency of f01 = 0.1 Hz, f02 = 30 Hz, f03 = 300 Hz and corresponding effective trap density (Neff) of the GR centers are obtained. By changing the LFN measurement temperature, a trap activation energy level (Ea) of 0.12 eV is extracted from an Arrhenius plot. The dominant mechanism of the 1/f noise for the H-terminated diamond FETs follows the correlated mobility fluctuations (CMF) model. By fitting the experimental data to the CMF model, the trap density and scattering coefficient of the carriers are extracted to be 6.4×1020 eV−1 cm−3 and 4×105 V·s/C. At last, the trap density of the H-terminated diamond FETs is compared with other state-of-the-art GaN and Si based devices. A moderate trap density was obtained without any interface optimization, suggesting that H-terminated diamond FETs could be a promising future technology for power electronics.

Electrical Noise Analysis of Z Shape Horizontal Pocket and Hetero Stack TFETs under Trap Distribution

In this work, a comprehensive investigation on noise analysis for two different low power devices, namely Z-shaped Horizontal Pocket (ZHP) and Hetero Stack (HS) TFETs, is presented within low to high frequency range. The simulation is performed for these structures in the presence of Uniform and Gaussian trap distributions at the interface of Silicon and oxide materials for three different noise namely Flicker noise, Generation Recombination (GR) noise, and Diffusion noise with the help of the Sentaurus TCAD simulator. The result reveals that Flicker and GR noise are dominates at Low Frequency, while, the diffusion noise reports significant influence at the high-frequency range. Finally, a comparative analysis has been done in terms of noise current spectral density (Sid) of the considered structures with the existing literature.

Generation–recombination noise in uniformly doped semiconductors with contacts of finite surface recombination velocities

The formula for the voltage noise spectrum due to generation–recombination (G–R) rate fluctuations is derived for uniformly doped majority-carrier n-type semiconductor samples with contacts of finite surface recombination velocities. In the derivation of the formula, a new boundary condition with finite surface recombination velocities considered is used instead of the ohmic boundary condition. The G–R voltage noise spectra are calculated to become saturated and equal in the high electric field region irrespective of surface recombination velocities. However, the behaviors of slow surface recombination velocities in the low electric field region differ from those of fast ones. The profiles of the electron density fluctuations of slow ones differ significantly from those of fast ones in the low-field region. In the high field region, a steep rise in the magnitude of the electron density fluctuation occurs near the voltage contact toward which electrons drift. The various location dependencies of the contribution of noise sources to the voltage power spectral density are also derived for low and high field regions as well as low and high surface recombination velocities, and analytical expressions are developed for the voltage power spectral densities and electron density fluctuations.

Low to high-frequency noise behavior investigation of steeper sub-threshold swing NC-GeFinFET

The role of noise effect, in presence of Gaussian-trap distribution on the negative capacitance germanium FinFET (NC-GeFinFET) by using Sentaurus-TCAD is investigated. Incorporation of ferroelectric FE-layer in NC-GeFinFET, ION boosts by almost 18% compared to the baseline FinFET. Also steeper sub-threshold swing (SS) of 7.4 mV/decade is achieved by using the FE-layer of thickness (tfe) 6 nm at the room temperature. Result reports how the 1f noise and Generation-Recombination (G-R) noise plays an important role in net drain current spectral density (net Sid) for the proposed device up to mid frequency range, and the diffusion noise dominates in the high frequency range. This study highlights the analysis of net Sid with respect to frequency for different tfe. The minimum net Sid value 4.45 ×10−16 A2/Hz is achieved at 10 Hz, in presence of Gaussian-trap, for tfe 6 nm and is compared with the results for tfe 4 nm and 5 nm. This shows the importance of FE-layer in achieving low net Sid, especially in high frequency regime.

Generation-recombination noise and other features of doped silicon in a wide temperature range

The characteristics of the generation-recombination (g-r) process in silicon are investigated in a temperature range from 25 to 360 K. In the case of shallow donors, it is shown that the free electron density strongly depends on temperature: only 20% of donors are ionized at shallow donor densities of about 1017 cm-3 at liquid nitrogen temperature. The maximum of the variance of generation-recombination noise due to the free electron density fluctuations for a silicon sample with shallow donors strongly increases with donor density and shifts with temperature. It is demonstrated that the relative variance of free electron number fluctuations is always equal to 0.5 at low temperatures. The normalized generation-recombination noise spectra are depicted in a very wide frequency range. There is also a detailed investigation of the generation-recombination noise characteristics of an acceptor-partially compensated silicon sample with two donor levels. In this work, the main focus is on the characteristics of silicon doped by shallow donors as it is extremely widely used.

Noise Processes and Nonlinear Mechanisms in Optoelectronic Phase-Locked Loop Using a Balanced Optical Microwave Phase Detector

This article analyses the effect of noise and nonlinearity in optoelectronic phase-locked loops (OEPLLs). The OEPLL phase-locks a microwave oscillator on the envelope of the optical pulse train from a mode-locked laser (MLL). The phase detector of this type of OEPLL is called a balanced optical microwave phase detector (BOMPD) and operates in a mixed electro-optical domain. The main noise sources in a BOMPD, such as shot noise of photodiodes, generation-recombination noise of photodiodes, relative intensity noise of the laser, and noise of the bias voltage applied to the BOMPD. are discussed. The nonlinear behavior of the BOMPD with respect to the intensity of the optical field and the amplitude of the RF voltage is discussed. An OEPLL that can lock on the harmonics and interharmonics of the MLL repetition rate is demonstrated. The OEPLL has an in-band phase noise of below −150 dBc/Hz at 100-kHz offset frequency for a carrier frequency of 10 GHz. This phase noise level is 10–20 dB better than state-of-the-art commercial frequency synthesizers.

(Electronics and Photonics Division Award) The Impact of Defects on the Performance of Semiconductor Devices and Materials

Since the early days of the semiconductor industry, defect control has been key to the successful development of devices and circuits. It requires a thorough understanding of their formation and the impact on the electrical material parameters. This has only been possible by the invention of powerful structural, chemical and electrical characterization tools, with the device itself perhaps as the most sensitive probe. This evolution was paralleled by the development of ab initio calculation methods, based on Density Functional Theory and more recently, also TCAD tools allowing more and more refined modelling of the impact of defects on the electrical characteristics of devices.The implementation of other materials than Si and SiO2 in CMOS through the hetero-epitaxial growth on a silicon substrate for example, has renewed the interest in defect engineering during the last two decades, leading to single-defect analysis methods like Random Telegraph Noise (RTN) [1] or novel growth schemes like Aspect Ratio Trapping (ART) [2] for the removal of extended defects from the device active regions.In this presentation, some state-of-the-art analysis techniques will be highlighted, including Deep Level Transient Spectroscopy (DLTS) [3], Generation-Recombination (GR) noise and RTN spectroscopy [1,4] and p-n diode lifetime analysis [5]. These methods will be applied to several case studies. As shown in Fig. 1, threading extended defects impact the recombination lifetime of lowly-doped n-type In0.47Ga0.53As starting from a density of a few 107 cm-2. Likewise, it will be demonstrated that the GR noise observed in GaN-on-Si MOSHEMTs (Fig. 2) most likely originates from threading dislocations [6]. It is concluded that when hetero-epitaxial layers can be grown with a sufficiently low defect density, their impact will be more on the variability of the electrical parameters rather than on the effective values. In addition, the position of the defect with respect to strategic nodes like a p-n junction or depletion region largely determines its electrical impact, as has been validated by TCAD simulations.

Role of gate electrode in influencing interface trap sensitivity in SOI tunnel FETs

This article reports the response of a silicon-on-insulator tunnel field-effect transistor (TFET) to the presence of semiconductor/ gate dielectric interface traps. A systematic strategy is designed keeping in view different parameters which are related to the gate of the device. Acceptor-like traps, and donor-like traps with Gaussian distribution are considered at the said interface for the entire analysis. Sensitivity % is taken as a figure of merit which measures the deviation of the drain current in presence of traps from the cases with no traps. The effect of temperature on interface traps, and the effect of interface traps on gate leakage current are analyzed. The acceptor-like traps are found to affect the on-state regime, and the donor-like traps are found to affect the ambipolar regime. Analyses on gate–drain underlap, gate–source overlap, shift of entire gate over the device, and gate work-function suggest that the gate electrode plays an important role in determining the sensitivity of the TFETs. Furthermore, noise spectral densities in presence of flicker, diffusion, and monopolar generation-recombination noise sources, and interface traps are reported.

Excess noise in high-current diamond diodes

We report the results of an investigation of low-frequency excess noise in high-current diamond diodes. It was found that the electronic excess noise of the diamond diodes is dominated by the 1/f and generation-recombination noise, which reveals itself as Lorentzian spectral features (f is the frequency). The generation-recombination bulges are characteristic of diamond diodes with lower turn-on voltages. The noise spectral density dependence on forward current, I, reveals three distinctive regions in all examined devices—it scales as I2 at the low (I &amp;lt; 10 μA) and high (I &amp;gt; 10 mA) currents and, rather unusually, remains nearly constant at the intermediate current range. The characteristic trap time constants, extracted from the noise data, show a uniquely strong dependence on current. Interestingly, the performance of the diamond diodes improves with the increasing temperature. The obtained results are important for the development of noise spectroscopy-based approaches for device reliability assessment for high-power diamond electronics.

Terahertz superconducting kinetic inductance detectors demonstrating photon-noise-limited performance and intrinsic generation-recombination noise

Terahertz superconducting kinetic inductance detectors demonstrating photon-noise-limited performance and intrinsic generation-recombination noise

Low-frequency noise characterization of AlGaN/GaN HEMTs with and without a p-GaN gate layer

In this paper, low-frequency noise characteristics of commercial AlGaN/GaN high electron mobility transistors with different substrates and devices with and without a p-GaN gate layer are measured and discussed. The noise power spectral density (PSD) of various devices are compared and analyzed under linear-region operation. The 1/f noise behavior exhibits carrier number fluctuation as the dominant cause. Devices with p-GaN gate layer fabricated on Si substrate show the highest normalized noise PSD. Results show that not only flicker noise (1/f noise) exists but that it also accompanied by generation–recombination noise (g–r noise) in the device on SiC substrate. The extracted g–r noise related traps show an activation energy of ∼0.37 eV, which is mostly caused by spatial charges trapping/detrapping with the deep acceptor in the GaN buffer layer.

High-responsivity, self-driven visible-near infrared Sb2Se3 nanorod array photodetector.

Anisotropic antimony selenide (Sb2Se3) semiconductor has received considerable attention due to its unique one-dimensional crystal structure and corresponding superior and anisotropic optical and electronic properties. It is a promising material for a wide range of applications related to electronics and optoelectronics. Herein, we demonstrate a high-performance and self-powered Sb2Se3 nanorod array-based core/shell heterojunction detector fabricated on glass substate. The detector shows a wide spectral photoresponse range from visible to near-infrared (405-980 nm). The detector yields a detectivity of as high as 2.06×1012 Jones in the visible light (638 nm) and that of 1.82×1012 Jones (830 nm) at zero bias. Due to the strong built-in filed and excellent carrier transport, the detector exhibits ultrafast response speed at both rise (30 μs) and decay (68 μs) processes. Further analysis demonstrates that the noise is mainly generated from the 1/f noise in the low frequency range, while it is affected by the shot noise and generation-recombination noise in high frequency.

Low‐Frequency Electronic Noise in Quasi‐2D van der Waals Antiferromagnetic Semiconductor FePS3—Signatures of Phase Transitions

AbstractLow‐frequency current fluctuations, i.e., noise, in the quasi‐2D van der Waals antiferromagnetic semiconductor FePS3 with the electronic bandgap of 1.5 eV is investigated. The electrical and noise characteristics of the p‐type, highly resistive, thin films of FePS3 are measured at different temperatures. The noise spectral density is of the 1/f‐type over most of the examined temperature range but reveals well‐defined Lorentzian bulges, and increases strongly near the Néel temperature TN = 118 K (f is the frequency). Intriguingly, the noise spectral density attains its minimum at temperature T ≈ 200 K, which is attributed to an interplay of two opposite trends in noise scaling—one for semiconductors and another for materials with the phase transitions. The Lorentzian corner frequencies reveal unusual dependence on temperature and bias voltage, suggesting that their origin is different from the generation—recombination noise in conventional semiconductors. The obtained results are important for proposed applications of antiferromagnetic semiconductors in spintronic devices. They also attest to the power of the noise spectroscopy for monitoring various phase transitions.

Impact of Hot Carrier Aging on the 1/f and Random Telegraph Noise of Short-Channel Triple-Gate Junctionless MOSFETs

The low-frequency noise of short channel triple-gate junctionless (TG JL) MOSFET has been investigated in the frequency and time domains before and after hot carrier aging (HCA). The objective of this work is to investigate the interaction between HCA/flicker noise (1/f noise) and random telegraph noise (RTN) of short channel length device (L = 25 nm) exhibiting high density of interface traps. Significant variation in the noise spectral density has been observed between the fresh and the stressed device, related to the occurrence of generation-recombination (g-r) noise. Gate voltage dependence of g-r noise has been observed, assigned to gate dielectric traps and interface traps. In the fresh device, the noise is dominated by 1/f noise and multiple level RTN due to interface traps. In the stressed device, the 1/f noise is overlaid by multiple level RTN due to traps in the gate dielectric and at the gate insulator-silicon interface. The multiple level RTN relative amplitude can be described by the generic carrier number with correlated mobility fluctuations model as for the two level RTN detected in long channel devices (L = 65 and 95 nm).

Low frequency noise in P-InAsSbP/n-InAs infrared light emitting diode-photodiode pairs

Low frequency noise in P-InAsSbP/n-InAs infrared light emitting diode- photodiode pairs is investigated for the first time at 300 K. It is shown that photocurrent fluctuations under LED illumination are smaller than photocurrent fluctuations under a black body illumination. When the photodiode is illuminated by LED, the spectral noise density follows the 1/f dependence. In the case of a black body illumination we observe a significant contribution of generation-recombination noise.

Relaxation processes in silicon heterojunction solar cells probed via noise spectroscopy

We have employed state-of-the-art cross-correlation noise spectroscopy (CCNS) to study carrier dynamics in silicon heterojunction solar cells (SHJ SCs). These cells were composed of a light absorbing n-doped monocrystalline silicon wafer contacted by passivating layers of i-a-Si:H and doped a-Si:H selective contact layers. Using CCNS, we are able to resolve and characterize four separate noise contributions: (1) shot noise with Fano factor close to unity due to holes tunneling through the np-junction, (2) a 1/f term connected to local potential fluctuations of charges trapped in a-Si:H defects, (3) generation-recombination noise with a time constant between 30 and 50 μs and attributed to recombination of holes at the interface between the ITO and n-a-Si:H window layer, and (4) a low-frequency generation-recombination term observed below 100 K which we assign to thermal emission over the ITO/ni-a-Si:H interface barrier. These results not only indicate that CCNS is capable of reveling otherwise undetectable relaxation process in SHJ SCs and other multi-layer devices, but also that the technique has a spatial selectivity allowing for the identification of the layer or interface where these processes are taking place.