Low-frequency Noise Characteristics Research Articles

Urban 110 kV indoor substation noise analysis and control schemes: A real case study

As an important node in urban city, power substation provides the clean energy to thousands of households, ensuring a stable and high quality of urban life. However, the influence of noise emission from substation is always underestimated. With the improvement of environmental consciousness, making the substations quietly hidden in urban cities becomes an urgent issue which should be thoroughly considered. A real case is presented in this paper to vividly reflect how such a comprehensive noise issue is faced and tackled through proper techniques and novel applications. Based on the low-frequency noise characteristics of 110 kV power transformers and the limited space features of indoor substation, integrated noise control schemes are proposed with consideration of low-noise design of ventilation and heat dissipation systems. Dynamic vibration absorber is firstly investigated and designed to minimize the vibration of transformer tank. After the practical implementation, the acoustic environment is reevaluated and the measurement results verified the noise control effect. Consequently, the acoustic environment quality within and out of substation is improved and the negative impact of urban substation is controlled.

Optimization of post-deposition annealing temperature for improved signal-to-noise ratio in In2O3 gas sensor

This paper investigates the effects of post-deposition annealing (PDA) temperature on H2S gas sensing and low-frequency noise characteristics of In2O3 gas sensors. In2O3 thin-films are deposited using the radio frequency (RF) sputtering method at an RF power of 150 W and post-annealed at various temperatures (200, 300, and 400 °C). The response of the In2O3 gas sensor to H2S decreases with increasing PDA temperature due to the increase of grain size. However, the In2O3 post-annealed at 200 °C shows the largest 1/f noise since the damaged sensing material-substrate interface is not fully recovered by the PDA. The sensors post-annealed at a higher temperature (300 °C and 400 °C) recover the damaged interface. Thanks to its moderate response and noise level, the sensor post-annealed at 300 °C shows the largest signal-to-noise ratio.

Low-Frequency noise investigation of AlGaN/GaN high-electron-mobility transistors

In this paper, the noise Power Spectral Density (PSD) of AlGaN/GaN High-Electron-Mobility Transistors (HEMTs) has been experimentally investigated in linear operation (VD = 50 mV) for different channel lengths (L) and widths (W) at different temperatures (5.32 °C till 100 °C). The origin of the noise will be analyzed to understand the physical mechanisms involved. It is shown that the Low-Frequency (LF) noise is dominated by 1/f noise, originating from number fluctuations. Additionally, in shorter devices, a higher 1/f noise PSD is found. The LF noise characteristics indicate that the AlGaN/GaN HEMTs on silicon substrates can be a promising candidate for analog and Radio Frequency applications (RF).

Effects of IGZO film thickness on H2S gas sensing performance: Response, excessive recovery, low-frequency noise, and signal-to-noise ratio

In this work, we investigate the effects of IGZO film thickness on the H2S gas sensing performance, such as response, excess recovery, low-frequency noise (LFN), and signal-to-noise ratio (SNR) in the resistor- and FET-type gas sensors. A transition of the dominant sensing area from the surface to the bulk of the IGZO film is observed with increasing film thickness. Also, excessive recovery is observed and its detailed mechanism is analyzed for the first time. The resistor-type gas sensor with thicker IGZO film has a smaller 1/f noise due to the decreased trap density and impurity scattering, which guarantees the largest SNR and the lowest limit of detection (LOD). In the case of the FET-type gas sensor, the thicker film with high porosity allows H2S gas to diffuse more easily into the IGZO-O/N/O interface and increases the response. Also, the LFN characteristics of the FET-type gas sensor have no dependence on the IGZO film thickness. Thus, the SNR of the FET-type gas sensor is the largest when the IGZO film thickness is 60 nm.

Trap Recovery by in-Situ Annealing in Fully-Depleted MOSFET With Active Silicide Resistor

This work reports first original results on the impact of active in-situ electro-thermal recovery, on the electrical and low-frequency noise characteristics of N-type MOS transistor with thick high-k metal gate oxide, from 28 nm Fully Depleted Silicon-On-Insulator (FDSOI) process. In order to recover “typical” device characteristics, four cycles of local thermal annealing up to 590K are applied for 14 ms each, using an active silicide source. Experimental results reveal an important improvement of the “corner” transistor’s I-V behavior allowing the recovery of “typical” device characteristics. An increase of the maximum transconductance by 43% is obtained. In the same time, a typical device stays unaffected by this local annealing. Low-frequency noisemeasurements showa clear reduction of the 1/f noise and Random Telegraph Noise by almost one decade, after the electro-thermal recovery. This can explain the improvement of the electrical characteristics by annealing of defects.

Comparison of the characteristics of semiconductor gas sensors with different transducers fabricated on the same substrate

Abstract The semiconductor-type gas sensor consists of a transducer and a sensing material. Most of the research on the sensor has focused on sensing materials. In this study, the characteristics of gas sensors using three different transducers (MOSFET, resistor, and TFT) are compared. For a fair comparison, the three types of gas sensors are fabricated through the same process on one chip and have the same sensing material. Indium oxide (In2O3) and NO2 gas are used as the sensing material and the target gas, respectively. The low-frequency noise (LFN) characteristics, response, signal to noise ratio (SNR), and limit of detection (LOD) of the three types of gas sensors are investigated and compared. Since the MOSFET-type gas sensor uses crystalline Si as the current path, the current normalized noise of the sensor is ∼105 smaller than that of the resistor- and TFT-type gas sensors using polycrystalline In2O3 as the current path. However, when reacting to 500 ppb NO2 gas, the response is the smallest in the MOSFET-type gas sensor and the largest in the TFT-type gas sensor (MOSFET: ∼2.3 × 102, resistor: 3.3 × 103 and TFT: ∼3.2 × 107). The SNR is large in order of TFT-, MOSFET-, resistor-type gas sensor over the entire range of measured gas concentrations (20 ∼ 500 ppb). The LODs of TFT-, MOSFET- and resistor-type gas sensors are 0.017, 0.300, and 26.3 ppb respectively. Considering the response, SNR and LOD, the TFT-type gas sensor is the best among the three-types of sensors.

Impacts of Program/Erase Cycling on the Low-Frequency Noise Characteristics of Reconfigurable Gated Schottky Diodes

In this work, the low-frequency noise (LFN) characteristics of reconfigurable field-effect-transistor (RFET), gated Schottky Diode (GSD), are investigated. The GSD has a different 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}$ </tex-math></inline-formula> noise origin depending on the operation mode ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula> - or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}$ </tex-math></inline-formula> -type FET mode) and current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{\mathbf {O}}$ </tex-math></inline-formula> ) region (low or high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{\mathbf {O}}$ </tex-math></inline-formula> region). Depending on the 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}$ </tex-math></inline-formula> noise origin, the effects of the program/erase (P/E) cycling differs. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}$ </tex-math></inline-formula> -type mode GSD operating in the high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{\mathbf {O}}$ </tex-math></inline-formula> region whose 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}$ </tex-math></inline-formula> noise is originated from the carrier number fluctuation (CNF) shows the largest noise increase after the 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> P/E cycling.

Improved low-frequency noise in CVD bilayer MoS2 field-effect transistors

In MoS2 field-effect transistors, the current or voltage fluctuations related to either mobility- or number-dependent relationships are characterized by low-frequency noise. This noise can typically be used to evaluate the application limits of MoS2-based electronic devices. In this work, the low-frequency noise characteristics of single-crystal bilayer MoS2 grown by chemical vapor deposition (CVD) are systematically investigated and found to offer significant performance improvements compared with those based on the monolayer MoS2 channel. At f = 100 Hz, the normalized drain current power spectral density (SI/Id2) is 2.4 × 10−10 Hz−1 and 3.1 × 10−9 Hz−1 for bilayer and monolayer MoS2 transistors, respectively. The 1/f noise behavior can be accurately described by McWhorter's carrier number fluctuation model for both transistor types, suggesting that carrier trapping and de-trapping by dielectric defects is the dominant mechanism of 1/f noise in CVD MoS2 transistors. Furthermore, a minimal WLSI/Id2 of 3.1 × 10−10 μm2/Hz (where W is the gate width and L is the gate length) is achieved at Vbg = 3 V by effectively reducing the contact resistance of bilayer MoS2 transistors using a back-gate voltage. These results demonstrate that CVD bilayer MoS2 is a promising candidate for future large-scale 2D-semiconductor-based electronic applications with improved noise performance.

Analysis of low frequency noise in in situ fluorine-doped ZnSnO thin-film transistors

We report on in situ fluorine-doped ZnSnO (ZTO:F) thin-film transistors (TFTs) fabricated by co-sputtering. The low frequency noise (LFN) characteristics of ZTO:F TFTs under different annealing temperatures and FSnO (FTO) deposition powers are comparatively studied for the first time. The results show that ZTO:F TFTs have the best electrical and LFN characteristics under an FTO deposition power of 25 W and an annealing temperature of 350 °C, while the saturated field effect mobility was measured to be 14.0 cm2 V−1 s−1, the switching current ratio is over 109, and the Hooge parameter is about 10−2 without any passivation. ZTO:F TFTs without rare metals have the potential for low-cost and environmentally safe manufacturing.

Investigation of Low-Frequency Noise Characteristics in Gated Schottky Diodes

In this work, the low-frequency noise (LFN) characteristics of the 3-terminal ${n}$ -type gated Schottky diode (GSD) were investigated. The GSD shows the 1/ ${f}$ noise behavior, and the noise origin depends on the operating current ( ${I}_{\text{D}}$ ) of the GSD. The 1/ ${f}$ noise is mainly generated by the barrier height fluctuation near the metal-semiconductor interface at the reverse Schottky diode (SD) in the low ${I}_{\text{D}}$ region, and by the carrier number fluctuation (CNF) at the ${n}$ -type FET in the high ${I}_{\text{D}}$ region. The LFN characteristics in the low $I_{\text{D}}$ region are strongly affected by the temperature. With increasing temperature, the transition of the $1/f$ noise origin from the reverse SD to the $n$ -type FET occurs at lower $I_{\text{D}}$ .

Influence of Buried Oxide Si+ Implantation on TID and NBTI Effects for PDSOI MOSFETs

The total ionization dose (TID) effect and negative bias temperature instability (NBTI) effect of 130-nm partially-depleted silicon-on-insulator (PDSOI) MOSFETs fabricated on hardened wafers with silicon ion implantation and unhardened wafers are investigated. A TID-hardened PDSOI MOSFET up to 1 Mrad(Si) is obtained by Si+ implantation in buried oxide (BOX). The hardening benefits from the electron traps in the BOX introduced by Si+ implantation. Although the radiation hardening process has a rare impact on nominal electrical characteristics of the device before irradiation, it will affect the NBTI reliability, which is manifested as the decrease in the NBTI lifetime for the radiation-hardened devices. The energy distribution of positive charges built up during NBTI stress is obtained. It proves that more damage-related traps exist near the gate oxide/silicon interface for the radiation-hardened device, which accelerates the threshold voltage shift during the NBTI stress. This conclusion is also verified by the low-frequency noise characteristics.

Effect of Hydrogen on Long-Term Reliability of InZnO TFTs Characterized by Low-Frequency Noise

The long-term reliability of InZnO (IZO) thin film transistors (TFTs) under a hydrogen-containing environment is researched. Hydrogen incorporation induces hydroxyl groups and oxygen vacancies, leading to the generation of electrons and extra random trap/emission processes in the IZO films. Consequently, the electrical properties and low frequency noise characteristics of IZO TFTs are deteriorated under the long-term hydrogen treatment. Additionally, the recovery characteristics of IZO TFTs after the hydrogen treatment demonstrate that the hydrogen induced hydroxyl groups and oxygen vacancies remain stable at room temperature. The oxygen vacancies can be eliminated, while the hydroxyl groups may still exist at a high temperature. These results may provide useful guidelines in the design and application of IZO TFTs.

伽马射线辐照增益光纤对光纤放大器低频噪声特性的影响

伽马射线辐照增益光纤对光纤放大器低频噪声特性的影响

Analysis of low frequency noise characteristics of praseodymium doped indium gallium oxide thin film transistor

Metal oxide thin film transistors (MOTFTs) have been extensively investigated in the display industry because of their attractive characteristics, including high performances, low processing temperatures, and simple fabrication. However, under the actual working condition, the characteristics of TFTs are easily affected by the light irradiation caused the negative gate bias stress (NBIS). Therefore, the NBIS stability of MOTFT is a crucial issue that must be solved before their commercialization into an optoelectronic device. In this article, praseodymium-doped indium gallium oxide (PrIGO) is employed as the channel layer of thin film transistor (TFT). The TFTs with Pr doping exhibit a remarkable enhancement in NBIS stability. The structure and chemical composition of PrIGO film are analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. Besides, to further explore the mechanism for the improvement of NBIS stability, the low-frequency noise characteristics of IGO-TFT device and PrIGO-TFT device are studied. According to the low frequency noise characterization and analysis results, the correspondence between the normalized drain current noise power spectral density(&lt;inline-formula&gt;&lt;tex-math id="Z-20210823100314-1"&gt;\begin{document}$ S_{\rm ID}/I_{\rm DS}^2 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210368_Z-20210823100314-1.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210368_Z-20210823100314-1.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;) and frequency shows 1/&lt;i&gt;f&lt;sup&gt;γ&lt;/sup&gt;&lt;/i&gt; (&lt;i&gt;γ&lt;/i&gt; ≈ 0.8) low frequency noise behavior for IGO-TFT device and PrIGO-TFT device. In addition, by studying the influences of different channel lengths on the low frequency noise of the IGO-TFT and PrIGO-TFT devices, it can be concluded that the low frequency noise of the device comes mainly from the channel region rather than from the source/drain contact region. In the linear region of the IGO-TFT device and PrIGO-TFT device, according to the linear fitting of the &lt;inline-formula&gt;&lt;tex-math id="Z-20210823100337-1"&gt;\begin{document}$ S_{\rm ID}/I_{\rm DS}^2 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210368_Z-20210823100337-1.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210368_Z-20210823100337-1.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt; versus the overdrive voltage (&lt;i&gt;V&lt;/i&gt;&lt;sub&gt;GS &lt;/sub&gt;– &lt;i&gt;V&lt;/i&gt;&lt;sub&gt;th&lt;/sub&gt;), it is proved that the low frequency noise of the IGO-TFT device and the PrIGO-TFT device are mainly affected by the carrier number fluctuation model. Finally, based on the carrier number fluctuation model, the defect state density at the interface between active layer and gate insulating layer is extracted to be 7.76 × 10&lt;sup&gt;17&lt;/sup&gt; cm&lt;sup&gt;–3&lt;/sup&gt;·eV&lt;sup&gt;–1&lt;/sup&gt; and 9.55 × 10&lt;sup&gt;17&lt;/sup&gt; cm&lt;sup&gt;–3&lt;/sup&gt;·eV&lt;sup&gt;–1&lt;/sup&gt; for IGO-TFT and PrIGO-TFT devices, respectively. We speculate that the Pr element can induce defect states in the IGO system, and the trap states induced by Pr ions facilitate the capture of free electrons by positively charged oxygen vacancies, which lead the photo-induced carrier in conduction band to be suppressed.

伽马射线辐照增益光纤对光纤放大器低频噪声特性的影响

伽马射线辐照增益光纤对光纤放大器低频噪声特性的影响

Degradation Behavior and Trap Analysis Based on Low-Frequency Noise of AlGaN/GaN HEMTs Subjected to Radio Frequency Overdrive Stress

In this article, the degradation behavior of the electrical characteristics of AlGaN/GaN HEMTs subjected to radio frequency (RF) overdrive stress has been studied. Trap analysis based on low-frequency noise (LFN) and electroluminescence (EL) characterizations was carried out for AlGaN/GaN HEMTs before and after RF stress. The experimental results show that drain-to-source current of AlGaN/GaN HEMTs after RF stress is obviously lower than that of the fresh devices. The maximum change of drain-to-source current was up to 79 mA in the saturation zone. The threshold voltage drifted forward and gate-lag characteristic became worse for the AlGaN/GaN HEMTs after RF stress. The EL characterizations also showed the nonuniformity of channel illumination intensity, which indicates the distribution of electron of the channel nonuniform. Trap analysis was performed by using the LFN method, and the LFN results showed that the trap density increased by about one order of magnitude in the AlGaN/GaN HEMTs after RF stress, which would lead to more depletion of the channel two-dimensional electron gas (2DEG) electrons. The mechanism of increasing trap density could be attributed to defects induced by RF stress at AlGaN surface and AlGaN barrier layer. The experimental results may offer a useful reference in the design and application of RF of AlGaN/GaN HEMTs.

Temperature dependence of conduction and low frequency noise characteristics in GaN Schottky barrier diodes

In this paper, the forward bias conduction and low frequency noise (LFN) characteristics of GaN Schottky barrier diodes (SBDs) have been measured and studied in the temperature range from 300 K to 450 K. Based on I–V measured results, the temperature dependence of ideality factor and zero bias Schottky barrier height reveals the inhomogeneities of Schottky barriers at the metal-semiconductor (MS) interface. Further study of the LFN measured results shows that the flicker noise ([Formula: see text] noise) is the main component of LFN in GaN SBDs. The current dependence of LFN indicates the influences of the Schottky barrier and the series resistance on [Formula: see text] noise, and the temperature dependence of LFN is analyzed according to Luo’s model and the barrier inhomogeneities model.

Low-frequency noise measurements as an analysis and prediction tool for the reliability evaluation of 808 nm laser diodes.

We investigated the low-frequency optical and electrical noise characteristics and their cross-correlation factor of the 808 nm laser diodes (LDs) samples, whose performances were degraded and stabilized after operating a period of time or during ex-factory reliability lifetime tests. It was shown that the optical noise in unreliable samples exhibited white components in the frequency range from 1 kHz to 10 kHz, while a Lorentzian-type component was superimposed on 1/f electrical noise. Meanwhile, the optical and electrical noise correlation exhibited positive result. In contrast, both low-frequency optical and electrical noise presented pure 1/f-type fluctuations in stable samples. These presented results suggest that it is feasible to employ low-frequency noise measurements as a tool for predicting and diagnosing the reliability of LDs.

Observation of single phonon-mediated quantum transport in a silicon single-electron CMOS single-atom transistor by RMS noise analysis

We explore phonon-mediated quantum transport through electronic noise characterization of a commercial CMOS transistor. The device behaves as a single electron transistor thanks to a single impurity atom in the channel. A low noise cryogenic CMOS transimpedance amplifier is exploited to perform low-frequency noise characterization down to the single electron, single donor and single phonon regime simultaneously, not otherwise visible through standard stability diagrams. Single electron tunneling as well as phonon-mediated features emerges in rms-noise measurements. Phonons are emitted at high frequency by generation-recombination phenomena by the impurity atom. The phonon decay is correlated to a Lorentzian 1/f 2 noise at low frequency.

Improved signal-to-noise-ratio of FET-type gas sensors using body bias control and embedded micro-heater

This paper investigates the effects of body-to-source junction bias (VBS) on signal-to-noise-ratio (SNR) of Si metal-oxide-silicon field effect transistor (FET)-type gas sensor with a localized embedded micro-heater. Sensing material, 12 nm-thick n-type semiconducting In2O3, is prepared through radio frequency magnetron sputtering. NO2 is used as a test gas to investigate the gas sensing characteristics of the sensor. By using the embedded micro-heater, the temperature of the sensing area can be raised to an extent required for the gas reaction (150 °C) while maintaining the temperature of the FET channel at 27 °C. The 1/f noise of the FET-type gas sensor is dominated by the carrier number fluctuation (CNF) in all operation regions. The effects of VBS on low-frequency noise (LFN) characteristics are demonstrated by the CNF model with correlated carrier mobility fluctuation. When a forward VBS of 0.5 V is applied to the sensor, the 1/f noise decreases by the factor of ∼10 and the SNR of the sensor increases by ∼2 times compared to when a VBS of 0 V is applied. It is shown that the limit of detection (LOD) of the gas sensor for NO2 gas can be improved from 0.55 ppb to 0.27 ppb by applying a forward VBS of 0.5 V.