Flicker Noise Characteristics Research Articles

Impact of fast and slow transient charging effect on reliability instability in In0.7Ga0.3As quantum-well MOSFETs with high-κ dielectrics

The impact of the fast and slow transient charge effect within defect sites of high-κ dielectrics for Al2O3 and bi-layer Al2O3/HfO2 In0.7Ga0.3As quantum-well (QW) MOSFETs was investigated in this report. In particular, the initial rapid degradation of the drain current for bi-layer Al2O3/HfO2 In0.7Ga0.3As QW MOSFETs was due to the fast transient charging effect. The continued decrease of the drain current with pulse time was attributed to the slow transient charging effect, which is located near the interface oxide traps to respond to increased charging time. The degradation of drain current for bi-layer Al2O3/HfO2 In0.7Ga0.3As QW MOSFETs was much higher than that of the Al2O3 In0.7Ga0.3As QW MOSFET, which is associated with reliability instability of the HfO2 layer for In0.7Ga0.3As QW MOSFETs. The detailed reliability instability mechanism for bi-layer Al2O3/HfO2 In0.7Ga0.3As QW MOSFETs was analyzed based on the fast/slow transient charge effect and flicker (1/f) noise characteristics.

Giant Conductance Enhancement of Intramolecular Circuits through Interchannel Gating

Summary For neutral intramolecular circuits with two constitutionally identical branches, a maximum 4-fold increase in total conductance can be obtained according to constructive quantum interference (CQI). For charged intramolecular circuits, however, the strong electrostatic interactions entangle the quantum states of these two parallel pathways, thus introducing complicated transport behavior that warrants experimental investigation of the intramolecular circuit rules. Here, we report that a tetracationic cyclophane with parallel channels exhibits a 50-fold conductance enhancement compared with that of a single-channel control, an observation that supplements intramolecular circuit law in systems with strong Coulombic interactions. Flicker noise measurements and theoretical calculations show that strong electrostatic interactions between charged parallel channels—serving as the chemical gate to promote the effective conductance of each channel—and CQI boosts the total conductance of the two-channel circuit. The molecular design presented herein constitutes a proof-of-principle approach to charged intramolecular circuits that are desirable for quantum circuits and devices.

The Impact of the Shallow-Trench Isolation Effect on Flicker Noise of Source Follower MOSFETs in a CMOS Image Sensor.

The flicker noise of source follower transistors is the dominant noise source in image sensors. This paper reports a systematic study of the shallow trench isolation effect in transistors with different sizes under high temperature conditions that correspond to the quantity of empty defect sites. The effects of shallow trench isolation sidewall defects on flicker noise characteristics are investigated. In addition, the low-frequency noise and subthreshold swing degrade simultaneously in accordance to the device gate width scaling. Both serious subthreshold leakage and considerable noise can be attributed to the high trap density near the STI edge. Consequently, we propose a coincidental relationship between the noise level and the subthreshold characteristic; its trend is identical to the experiments and simulation results.

Generalized Noise Study of Solid-State Nanopores at Low Frequencies.

Nanopore technology has been extensively investigated for analysis of biomolecules, and a success story in this field concerns DNA sequencing using a nanopore chip featuring an array of hundreds of biological nanopores (BioNs). Solid-state nanopores (SSNs) have been explored to attain longer lifetime and higher integration density than what BioNs can offer, but SSNs are generally considered to generate higher noise whose origin remains to be confirmed. Here, we systematically study low-frequency (including thermal and flicker) noise characteristics of SSNs measuring 7 to 200 nm in diameter drilled through a 20-nm-thick SiNx membrane by focused ion milling. Both bulk and surface ionic currents in the nanopore are found to contribute to the flicker noise, with their respective contributions determined by salt concentration and pH in electrolytes as well as bias conditions. Increasing salt concentration at constant pH and voltage bias leads to increase in the bulk ionic current and noise therefrom. Changing pH at constant salt concentration and current bias results in variation of surface charge density, and hence alteration of surface ionic current and noise. In addition, the noise from Ag/AgCl electrodes can become predominant when the pore size is large and/or the salt concentration is high. Analysis of our comprehensive experimental results leads to the establishment of a generalized nanopore noise model. The model not only gives an excellent account of the experimental observations, but can also be used for evaluation of various noise components in much smaller nanopores currently not experimentally available.

THE EFFECTS OF THE IONOSPHERE ON GROUND-BASED DETECTION OF THE GLOBAL 21 cm SIGNAL FROM THE COSMIC DAWN AND THE DARK AGES

ABSTRACT Detection of the global H i 21 cm signal from the Cosmic Dawn and the Epoch of Reionization is the key science driver for several ongoing ground-based and future ground-/space-based experiments. The crucial spectral features in the global 21 cm signal (turning points) occur at low radio frequencies . In addition to the human-generated radio frequency interference, Earth’s ionosphere drastically corrupts low-frequency radio observations from the ground. In this paper, we examine the effects of time-varying ionospheric refraction, absorption, and thermal emission at these low radio frequencies and their combined effect on any ground-based global 21 cm experiment. It should be noted that this is the first study of the effect of a dynamic ionosphere on global 21 cm experiments. The fluctuations in the ionosphere are influenced by solar activity with flicker noise characteristics. The same characteristics are reflected in the ionospheric corruption to any radio signal passing through the ionosphere. As a result, any ground-based observations of the faint global 21 cm signal are corrupted by flicker noise (or noise, where f is the dynamical frequency) which scales as (where ν is the frequency of radio observation) in the presence of a bright galactic foreground ( , where s is the radio spectral index). Hence, the calibration of the ionosphere for any such experiment is critical. Any attempt to calibrate the ionospheric effects will be subject to the inaccuracies in the current ionospheric measurements using Global Positioning System (GPS) ionospheric measurements, riometer measurements, ionospheric soundings, etc. Even considering an optimistic improvement in the accuracy of GPS–total electron content measurements, we conclude that Earth’s ionosphere poses a significant challenge in the absolute detection of the global 21 cm signal below 100 MHz.

Fractal dimension variability in ULF magnetic field with reference to local earthquakes at MPGO, Ghuttu

ABSTRACTUltra-low frequency (ULF) geomagnetic data recorded during 1 January 2010 to 31 December 2010 at multi-parametric geophysical observatory (30.53°N, 78.74°E) in Garhwal Himalaya region of Uttarakhand, India, are analyzed. From the temporal variation of polarization ratio, the presence of seismo-magnetic disturbances superposed upon background geomagnetic variations are inferred. Considering earthquake process as a self-organized critical system based on flicker noise characteristics, fractal dimension for each day is estimated using two methods namely power spectral (FFT) method and Higuchi method. Variability in fractal dimension is studied in the background of local earthquakes (M ≥ 3.5) within a zone of radius 150 km from observing station multi-parametric geophysical observatory (MPGO), Ghuttu. Fractal dimension variability indicates that average fractal dimension for first half of the year is increased as compared to average fractal dimension of second half of the year and there is gradual increase in the fractal dimension before earthquakes. It is also observed that during the first half of the year, there is seismic activity within zone of 150 Km radius centred at around MPGO, Ghuttu. There are no earthquakes during the second half of the year. Gradual increase in the fractal dimension before earthquakes, observed elsewhere in the world, is considered precursory signature of seismo-electromagnetic field emissions.

THE IMPACT OF THE IONOSPHERE ON GROUND-BASED DETECTION OF THE GLOBAL EPOCH OF REIONIZATION SIGNAL

The redshifted 21 cm line of neutral hydrogen (H i), potentially observable at low radio frequencies (∼50–200 MHz), is a promising probe of the physical conditions of the intergalactic medium during Cosmic Dawn and the Epoch of Reionization (EoR). The sky-averaged H i signal is expected to be extremely weak (∼100 mK) in comparison to the Galactic foreground emission (∼104 K). Moreover, the sky-averaged spectra measured by ground-based instruments are affected by chromatic propagation effects (∼tens of kelvin) originating in the ionosphere. We analyze data collected with the upgraded Broadband Instrument for Global Hydrogen Reionization Signal system deployed at the Murchison Radio-astronomy Observatory to assess the significance of ionospheric effects on the detection of the global EoR signal. The ionospheric effects identified in these data are, particularly during nighttime, dominated by absorption and emission. We measure some properties of the ionosphere, such as the electron temperature (Te ≈ 470 K at nighttime), magnitude, and variability of optical depth (τ100 MHz ≈ 0.01 and δτ ≈ 0.005 at nighttime). According to the results of a statistical test applied on a large data sample, very long integrations (∼100 hr collected over approximately 2 months) lead to increased signal-to-noise ratio even in the presence of ionospheric variability. This is further supported by the structure of the power spectrum of the sky temperature fluctuations, which has flicker noise characteristics at frequencies ≳10−5 Hz, but becomes flat below ≈10−5 Hz. Hence, we conclude that the stochastic error introduced by the chromatic ionospheric effects tends to zero in an average. Therefore, the ionospheric effects and fluctuations are not fundamental impediments preventing ground-based instruments from integrating down to the precision required by global EoR experiments, provided that the ionospheric contribution is properly accounted for in the data analysis.

Improved Device Performance of GaN/AlGaN High-Electron-Mobility Transistor Using PdO Gate Interlayer

We demonstrate significant improvements of GaN/AlGaN high-electron-mobility transistors (HEMTs) by employing a PdO gate interlayer, which exhibit device performance superior to that of Pd Schottky gate HEMTs. The PdO gate interlayer effectively reduces the gate leakage current by four orders of magnitude, and it also increases the ION/IOFF ratio to four orders of magnitude. The improved AlGaN/GaN/PdO HEMT shows a nearly ideal subthreshold slope of 66 mV/dec. The flicker noise characteristic is also observed to be lower in PdO-gate HEMTs than in Pd-Gate HEMTs. The high-work-function PdO layer and associated barrier height enhancement are the origins of the improved device performance.

Noise Properties of ZnO Nanowalls Deposited Using Rapid Thermal Evaporation Technology

ZnO nanowalls are rapidly grown on a glass substrate using a low-temperature thermal evaporation method, without the use of a catalyst and the pre-deposition of a ZnO seed layer on the substrate. Most of the ZnO nanowalls are grown vertically and are about 70-200-nm thick and 2-μm long. The room-temperature photoluminescence spectra show a strong intrinsic ultraviolet (UV) emission and a weak defect-related orange emission. The ZnO nanowall UV sensor is highly sensitive to UV light, with an excellent UV-to-visible ratio and good flicker noise characteristics. This shows the strong potential of ZnO nanowalls for use in UV sensors. At an applied bias of 2 V, the noise equivalent power and the normalized detectivity of the ZnO nanowall UV sensor are 1.87 × 10-10 W and 3.38 × 109 cm·Hz0.5·W-1, respectively.

Correlated Flicker Noise and Hole Mobility Characteristics of $(\hbox{110})/\langle\hbox{110}\rangle$ Uniaxially Strained SiGe FINFETs

Hole mobility and flicker noise characteristics of uniaxially strained <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$( \hbox{110})/\langle\hbox{110}\rangle$</tex></formula> <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{Si}_{0.75} \hbox{Ge}_{0.25}$</tex></formula> pFINFETs <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(\hbox{SSGOI}_{0.25})$</tex></formula> are investigated in this letter. Equivalent gate referred flicker noise in <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$ \hbox{SSGOI}_{0.25}$</tex></formula> is dominated by correlated number and mobility fluctuation in the low-bias regime and Hooge mobility fluctuation in the high-bias regime. The extracted Hooge parameter in <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{SSGOI}_{0.25}$</tex></formula> and in Si pFINFETs is <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{10}^{-5}$</tex></formula> and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$ \hbox{10}^{-4}$</tex></formula> , respectively. The lower value of the Hooge parameter in <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{SSGOI}_{0.25}$</tex></formula> pFINFETs is attributed to improved phonon-limited mobility compared to the SOI pFINFETs. <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{SSGOI}_{0.25}\ \hbox{FINFETs}$</tex></formula> are found to exhibit the lowest equivalent gate referred flicker noise among any nonplanar devices reported to date.

Plasma Nitrided Oxide와 Thermally Nitrided Oxide를 적용한 NMOSFET의 Flicker Noise와 신뢰성에 대한 비교 분석

In this paper, flicker noise characteristic and channel hot carrier degradation of NMOSFETs with plasma nitrided oixde (PNO) and thermally nitrided oxide (TNO) are analyzed in depth. Compared with NMOSFET with TNO, flicker noise characteristic of NMOSFET with PNO is improved significantly because nitrogen density in PNO near the Si/ interface is less than that in TNO. However, device degradation of NMOSFET with PNO by channel hot carrier stress is greater than that with TNO although PMOSFET with PNO showed greater immunity to NBTI degradation than that with TNO in previous study. Therefore, concurrent investigation of the reliability as well as low frequency noise characteristics of NMOSFET and PMOSFET is required for the development of high performance analog MOSFET technology.

Effect of Nitrogen Concentration on Low-Frequency Noise and Negative Bias Temperature Instability of p-Channel Metal–Oxide–Semiconductor Field-Effect Transistors with Nitrided Gate Oxide

In this paper, the dependence of negative bias temperature instability (NBTI) and low-frequency noise characteristics on the various nitrided gate oxides is reported. The threshold voltage shift (ΔVT) under NBTI stress for thermally nitrided oxide (TNO) was greater than that of plasma nitrided oxide (PNO), whereas the slopes of ΔVT versus stress time for PNO were similar to those for TNO. The flicker noise (1/f noise) characteristic of PNO was better than that of TNO by about 1 order of magnitude, although the 1/f noise of PNO showed almost the same dependence on the frequency as that of TNO. The carrier number fluctuation model due to the trapping and detrapping of electrons in oxide traps was found to be a dominant mechanism of flicker noise. The probability of the generation of drain current random telegraph signal (ID–RTS) noise shows similar values (70–78%) for all nitrided oxides, which shows that the generation of RTS noise is not greatly affected by the nitridation method or nitrogen concentration.

On-State and Off-State Breakdown Voltages in GaAs PHEMTs With Various Field-Plate and Gate-Recess Extension Structures

GaAs pseudomorphic high-electron mobility transistors (PHEMTs) with various field-plate (FP) and gate-recess (GR) extensions were fabricated. Their on-state resistance ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> ), breakdown voltage, flicker noise, and microwave characteristics were investigated. The FP length and GR width extensions can be controlled to improve significantly the breakdown voltage of PHEMTs. The design-of-experiment approach was employed with 16 transistors. The FP length extension was found to improve efficiently the off-state breakdown voltage ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BV</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ) because of its suppression of the thermionic-field emission of gate electrons. However, an FP-induced depletion region cannot easily suppress channel impact ionization, which dominates the on-state breakdown voltage ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BV</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> ). Additionally, the FP length extension reduces the flicker noise of a device that is caused by surface states. The GR width extension has an opposite effect, because the exposed area of the uncap Schottky layer exposure increases with the GR width.

AlGaN/GaN HEMTs With Low Leakage Current and High On/Off Current Ratio

In this letter, we propose using an oxide-filled isolation structure followed by N2/H2 postgate annealing to reduce the leakage current in AlGaN/GaN HEMTs. An off-state drain leakage current that is smaller than 10-9 A/mm (minimum 5.1 × 10-10 A/mm) can be achieved, and a gate leakage current in the range of 7.8 ×10-10 to 9.2 × 10-11A/mm (V GS from -10 to 0 V and V DS = 10 V) is obtained. The substantially reduced leakage current results in an excellent on/off current ratio that is up to 1.5 × 108. An improved flicker noise characteristic is also observed in the oxide-filled devices compared with that in the traditional mesa-isolated GaN HEMTs.

Anomalous diffusion in the dynamics of complex processes

It is shown that complex signals represented in the form of time series of measured dynamic variables can contain chaotic components whose time changes can be described as anomalous diffusion processes. To determine the parameters of such processes, procedures for the extraction of low-frequency and highest-frequency flicker-noise components, which are flicker-noise spectroscopy characteristics, should be developed. The methodology of the corresponding analysis is demonstrated for the example of magnetoencephalogram signals recorded as responses to the external action of a flickering color stimulus.

Photometric variability of the T Tauri star TW Hya on time-scales of hours to years★

MOST (Microvariability & Oscillations of STars) and ASAS (All Sky Automated Survey) observations have been used to characterize photometric variability of TW Hya on time scales from a fraction of a day to 7.5 weeks and from a few days to 8 years, respectively. The two data sets have very different uncertainties and temporal coverage properties and cannot be directly combined, nevertheless, they suggests a global variability spectrum with “flicker noise” properties, i.e. with amplitudes a / 1/ p f, over > 4 decades in frequency, in the range f = 0.0003 to 10 cycles per day (c/d). A 3.7 d period is clearly present in the continuous 11 day, 0.07 d time resolution, observations by MOST in 2007. Brightness extrema coincide with zero-velocity crossings in periodic (3.56 d) radial velocity variability detected in contemporaneous spectroscopic observations of Setiawan et al. (2008) and interpreted as caused by a planet. The 3.56/3.7 d periodicity was entirely absent in the second, four times longer MOST run in 2008, casting doubt on the planetary explanation. Instead, a spectrum of unstable single periods within the range of 2 – 9 days was observed; the tendency of the periods to progressively shorten was well traced using the wavelet analysis. The evolving periodicities and the overall flicker-noise characteristics of the TW Hya variability suggest a combination of several mechanisms, with the dominant ones probably related to the accretion processes from the disk around the star.

STI-to-gate distance effects on flicker noise characteristics in 0.13 μm CMOS

The geometry effect on the flicker noise characteristics and the variations in 0.13μm CMOS transistors were studied. By symmetrically extending the distance between the shallow-trench-isolation (STI) to the gate, both NMOS and PMOS presented obvious improvement on the noise characteristics. As the distance increased from 0.6μm to 10μm, the average noise level reduced by more than one order of magnitude (NMOS) and the standard deviations σdB improved from 5.95dB to 1.79dB for NMOS and from 3.93dB to 2.17dB for PMOS, respectively. To further identify the noise mechanism, the devices with asymmetrical STI-to-gate distances were also investigated. It was found that the distance in the source side (SA) has a much higher impact on the observed noise characteristics. The results suggested that the noise characteristics were dominated by the STI stress induced traps for both NMOS and PMOS studied here. In addition, the carrier number fluctuation model with the correlated mobility scattering could be more suitable to describe the noise characteristics in these devices.

Flicker Noise and Its Degradation Characteristics Under Electrical Stress in MOSFETs With Thin Strained-Si/SiGe Dual-Quantum Well

This letter reports on the low-frequency flicker-noise characteristics in fresh and electrically stressed pMOSFETs with thin strained-Si (~4 nm)/Si0.6Ge0.4 (~4 nm) dual-quantum-well (DQW) channel architectures. Normalized power spectral density (NPSD) of Id fluctuations (SID/Id 2) in fresh DQW devices exhibits significant improvement (by >102times) due to buried channel operation at low Vg. At high Vg, the NPSD enhancement reduces as carriers populate in the parasitic surface channel. Upon electrical stress, noise behavior in DQW devices was found to evolve from being carrier number-fluctuation dominated to mobility- fluctuation dominated. This was accompanied by the observation of a less-distinct buried-channel operation, indicating a potential stability issue of the Si/SiGe structure.

Impact of STI Effect on Flicker Noise in 0.13-$\mu \hbox{m}$ RF nMOSFETs

This paper reports on the impact of shallow-trench isolation (STI) on flicker noise characteristics in 0.13-mum RF nMOSFETs. The drain noise current spectral density was measured in both triode and saturation regions for a more complete study. The devices with a relatively small finger width and a large finger number (W=1 mum/N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">finger</sub> =40 and W=5 mum/N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">finger</sub> =8) presented more pronounced generation-recombination (G-R) noise characteristics compared to those with W=10 mum/N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">finger</sub> =4. In addition, a wide noise level variation of more than one order of magnitude was associated with the more obvious G-R noise components. The observed trends can be explained by the nonuniform stress effect of STI and also the associated traps at the edge of the gate finger between STI and the active region. To further study the noise mechanism, the single-linger devices with different STI-to-gate distances [SA(SB)=0.6,1.2, and 10 mum] were investigated. The measured results provided a direct evidence of STI effect on flicker noise characteristics. The activation energy of the traps was extracted at various temperatures in a range from E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> -0.397 to E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> -0.54 eV. Moreover, the calculated standard deviation sigma <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dB</sub> showed a strong dependence of noise variation on device geometry (sigma <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dB</sub> =2.95 dB for W=1 mum/N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">finger</sub> =40 and sigma <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dB</sub> =1.54 dB for W=10 mum/N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">finger</sub> =4). The analysis suggests that the carrier number fluctuation model with the correlated mobility scattering is more suitable for the noise characteristics in these devices.

DC and 1/f noise characteristics of InGaP/InGaAsN/GaAs double heterojunction bipolar transistors

A novel quaternary material of InGaAsN has been proposed as a base layer for GaAs-based double heterojunction bipolar transistors (DHBTs). By utilizing InGaAs as a base material, a lower band gap energy of the base layer in heterojunction bipolar transistors (HBTs) followed by a smaller turn-on voltage can be achieved. The 1/f noise characteristics of HBTs with an InGaAs base layer also show great improvement. Moreover, a smaller band gap base material of InGaAsN latticed-matched to a GaAs substrate can be obtained by incorporating suitable amounts of indium (In) and nitrogen (N) into GaAs base material, and thus enhance turn-on voltage reduction. In this study, dc and flicker noise characteristics of InGaAsN DHBTs are investigated by comparing GaAs and InGaAs DHBTs. The experimental results show that the 1/f noise has been found to depend on Ib as Iγb, where 1.95 < γ < 2.04 for the InGaP/InGaAsN DHBTs with high current gains (β ∼ 60). The 1/f noise of the InGaAsN sample is one order lower than that of the GaAs sample.