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1.
The influence of Al content on the RF noise characteristics of Al xGa1-xAs/GaAs heterojunction bipolar transistors (HBT's) is presented. It is shown that the minimum noise figure (Fmin) at 2 GHz is reduced by increasing the Al mole fraction (x). This observed improvement in noise figure is directly correlated to the differences in dc current gain. The lowest measured Fmin(2 GHz) of HBT's with emitter dimensions 2×(3.5×30) μm2, were 1.3, 1.61, and 2.1 dB for x=0.35, 0.30, and 0.25 devices, respectively at Ic=3 mA. The measured results were found to agree well with calculated values over a wide range of collector currents 相似文献
2.
Apostolakis P.J. Middleton J.R. Scherrer D. Feng M. Lepore A.N. 《Electron Device Letters, IEEE》1994,15(7):239-241
We report on the noise performance of low power 0.25 μm gate ion implanted D-mode GaAs MESFETs suitable for wireless personal communication applications. The 0.25 μm×200 μm D-mode MESFET has a ft of 18 GHz and fmax of 33 GHz at a power level of 1 mW (power density of 5 mW/mm). The noise characteristics at 4 GHz for the D-mode MESFET are Fmin=0.65 dB and Gassoc =13 dB at 1 mW. These results demonstrate that the GaAs D-mode MESFET is also an excellent choice for low power personal communication applications 相似文献
3.
Koester S.J. Hammond R. Chu J.O. Mooney P.M. Ott J.A. Perraud L. Jenkins K.A. Webster C.S. Lagnado I. de la Houssaye P.R. 《Electron Device Letters, IEEE》2001,22(2):92-94
The dc and microwave results of Si0.2Ge0.8/Si0.7Ge0.3 pMODFETs grown on silicon-on-sapphire (SOS) substrates by ultrahigh vacuum chemical vapor deposition are reported. Devices with Lg=0.1 μm displayed high transconductance (377 mS/mm), low output conductance (25 mS/mm), and high gate-to-drain breakdown voltage (4 V). The dc current-voltage (I-V) characteristics were also nearly identical to those of control devices grown on bulk Si substrates. Microwave characterization of 0.1×50 μm2 devices yielded unity current gain (fT) and unilateral power gain (f max) cutoff frequencies as high as 50 GHz and 116 GHz, respectively. Noise parameter characterization of 0.1×90 μm2 devices revealed minimum noise figure (Fmin) of 0.6 dB at 3 GHz and 2.5 dB at 20 GHz 相似文献
4.
Minority-carrier electron lifetime, mobility and diffusion length in heavily doped p-type Si were measured at 296 and 77 K. It was found that a 296 K μn (pSi)≈μn (nSi) for N AA≲5×1018 cm-3, while μn (pSi)/μn (nSi)≈1 to 2.7 for higher dopings. The results also show that for N AA≲3×1019 cm-3, D (pSi) at 77 K is smaller than that at 296 K, while for higher dopings D n (pSi) is larger at 77 K than at 296 K. μn (pSi) at 77 K increases with the increasing doping above N AA>3×1018 cm-3, in contrast to the opposite dependence for μn (nSi) in n+ Si 相似文献
5.
Whelan C.S. Hoke W.F. McTaggart R.A. Lardizabal M. Lyman P.S. Marsh P.F. Kazior T.E. 《Electron Device Letters, IEEE》2000,21(1):5-8
A double-pulse-doped InAlGaAs/In0.43Ga0.57As metamorphic high electron mobility transistor (MHEMT) on a GaAs substrate is demonstrated with state-of-the-art noise and power performance, This 0.15 μm T-gate MHEMT exhibits high on- and off-state breakdown (Vds>6 V and Vdg>13 V, respectively) which allows biasing at Vds>5 V. The 0.6 mm device shows >27 dBm output power (850 mW/mm) at 35 GHz-the highest reported power density of any MHEMT. Additionally, a smaller gate periphery 2×50 μm (0.1 mm) 43% MHEMT exhibits a Fmin=1.18 dB and 10.7 dB associated gain at 25 GHz, and also is the first noise measurement of a -40% In MHEMT. A double recess process with selective etch chemistries provides for high yields 相似文献
6.
The circuit performance of CMOS technologies with silicon dioxide (SiO2) and reoxidized nitrided oxide (RONO) gate dielectrics over the normal regime of digital circuit operation, i.e. V GS⩽5 V and B DS⩽5 V, is discussed. The simulation of a simple CMOS inverter has shown that the SiO2 inverter consistently outperforms the RONO inverter over temperatures ranging from 300 to 100 K. This can be attributed mainly to the significantly lower μp (hole mobility) of RONO p-channel devices. At 300 K, μp(RONO) is 14-8% smaller than μp(SiO2) over the entire range of gate biases, while μn(RONO) (electron mobility of n-channel RONO devices) is also smaller than μn(SiO2) and reaches only 96% of μn(SiO2) at V GS=5 V. At 100 K, μn(RONO)/μn (SiO2) at V GS=5 V is increased to 1.10, however, μp(RONO)/μp(SiO2) at V GS=5 V is degraded to 0.59. The dependence of circuit performance on the supply voltage has also been evaluated for the RONO and SiO2 inverters 相似文献
7.
A model to explain the noise properties for AlGaAs/GaAs HEMT's, AlGaAs/InGaAs/GaAs pseudomorphic HEMT's (P-HEMT's) and GaAs/AlGaAs inverted HEMT's (I-HEMT's) is presented. The model Is based on a self-consistent solution of Schrodinger and Poisson's equations. The influence of the drain-source current, frequency and device parameters on the minimum noise figure Fmin and minimum noise temperature Tmin, for different HEMT structures are presented. The study shows that P-HEMT's have a better noise performance than the normal and inverted HEMT's. The present model predicts that a long gate P-HEMT device will exhibit a better noise performance than a conventional HEMT. There is a range of doped epilayer thickness where minimum noise figure is a minimum for pseudomorphic HEMT's which is not observed in conventional and inverted HEMT's. The calculated noise properties are compared with experimental data and the results show excellent agreement for all devices 相似文献
8.
This paper analyzes the effects of the separation between the gate and the drain electrodes on the high-frequency performance limitations of heterostructure MODFET's. Based on the effective gate-length and carrier velocity saturation concepts first the key small-signal equivalent network model parameters of the MODFET are calculated. The concept of open-circuit voltage gain, defined as the transconductance to output conductance ratio (gm/go), has been exploited to determine the output conductance with a knowledge of the static electric field and potential at the edge of the gate on the drain side. By treating the coμn product as a function of the gate voltage, the drain current-voltage and transconductance characteristics have been effectively modeled for practical devices. By combining the effects of the intrinsic and parasitic equivalent network parameters this paper has determined the dependence of the gm/go ratio, the gate capacitance to the feedback capacitance ratio, the unity current gain frequency (fr) and the maximum frequency of oscillations (f max) on the gate-to-drain separation (Lgd). MODFET's based on InAlAs/InGaAs heterostructures lattice-matched to InP substrate with gate-length values of 0.25 μm, 0.15 μm and 0.1 μm are considered for analyses. The optimum values of Lgd calculated are 600 Å, 420 Å, and 340 Å for the corresponding maximum fmax-values of 250, 370, and 480 GHz, respectively 相似文献
9.
An analysis is presented of the changes of the noise parameters of a two-port network when noisy series and parallel feedback immittances are applied. Exact formulas for the noise parameters Rn, g n, and ρn are given as functions of the feedback for a given network. It is proved that Rn always reaches a minimum when a reactive series feedback is considered. The same results are demonstrated for gn since a duality principle is pointed out. The results are valid for a wide range of linear microwave two-port networks, either passive or active, and they are used to confirm the data from previously published work 相似文献
10.
Enciso M. Aniel F. Crozat P. Adde R. Zeuner M. Fox A. Hackbarth T. 《Electronics letters》2001,37(17):1089-1090
RF and microwave noise performances of strained Si/Si0.58 Ge0.42 n-MODFETs are presented for the first time. The 0.13 μm gate devices have de-embedded fT=49 GHz, fmax =70 GHz and a record intrinsic gm=700 mS/mm. A de-embedded minimum noise figure NFmin=0.3 dB with a 41 Ω noise resistance Rn and a 19 dB associated gain Gass are obtained at 2.5 GHz, while NFmin=2.0 dB with Gass=10 dB at 18 GHz. The noise parameters measured up to 18 GHz and from 10 to 180 mA/mm with high gain and low power dissipation show the potential of SiGe MODFETs for mobile communications 相似文献
11.
Onodera K. Nishimura K. Aoyama S. Sugitani S. Yamane Y. Hirano M. 《Electron Devices, IEEE Transactions on》1999,46(2):310-319
Fully ion-implanted low-noise GaAs MESFETs with a 0.11-μm Au/WSiN T-shaped gate have been successfully developed for applications in monolithic microwave and millimeter-wave integrated circuits (MMICs). In order to reduce the gate resistance, a wide Au gate head made of a first-level interconnect is employed. As the wide gate head results in parasitic capacitance, the relation between the gate head length (Lh) and the device performance is examined. The gate resistance is also precisely calculated using the cold FET technique and Mahon and Anhold's method. A current gain cutoff frequency (fT) and a maximum stable gain (MSG) decrease monotonously as Lh increases on account of parasitic capacitance. However, the device with Lh of 1.0 μm, which has lower gate resistance than 1.0 Ω, exhibits a noise figure of 0.78 dB with an associated gain of 8.7 dB at an operating frequency of 26 GHz. The measured noise figure is comparable to that of GaAs-based HEMT's 相似文献
12.
In this paper we present a new three-terminal test structure that enables one to simply evaluate the reduction in the hole and electron mobilities due to the carrier-carrier scattering effect. The use of a three-terminal device is necessary to remove the limitations of other measurement methods and to separately obtain μn and μ p. An investigation of the role of the geometrical parameters of the test structure highlights its suitability and flexibility for the mobility extraction procedure. Numerical simulation is used to carefully design the test structure and to verify the accuracy of the measurement method. Experimental results obtained from n-type silicon regions are presented and compared to major analytical models 相似文献
13.
Jagannathan B. Khater M. Pagette F. Rieh J.-S. Angell D. Chen H. Florkey J. Golan F. Greenberg D.R. Groves R. Jeng S.J. Johnson J. Mengistu E. Schonenberg K.T. Schnabel C.M. Smith P. Stricker A. Ahlgren D. Freeman G. Stein K. Subbanna S. 《Electron Device Letters, IEEE》2002,23(5):258-260
This paper reports on SiGe NPN HBTs with unity gain cutoff frequency (fT) of 207 GHz and an fMAX extrapolated from Mason's unilateral gain of 285 GHz. fMAX extrapolated from maximum available gain is 194 GHz. Transistors sized 0.12×2.5 μm2 have these characteristics at a linear current of 1.0 mA/μm (8.3 mA/μm2). Smaller transistors (0.12×0.5 μm2) have an fT of 180 GHz at 800 μA current. The devices have a pinched base sheet resistance of 2.5 kΩ/sq. and an open-base breakdown voltage BVCEO of 1.7 V. The improved performance is a result of a new self-aligned device structure that minimizes parasitic resistance and capacitance without affecting fT at small lateral dimensions 相似文献
14.
Asgaran S. Deen M. J. Chen C.-H. Rezvani G. A. Kamali Y. Kiyota Y. 《Solid-State Circuits, IEEE Journal of》2007,42(5):1034-1043
An analytical method, along with closed-form solutions, to determine high-frequency (HF) noise parameters of the MOSFET from its noise figure (NF) measurements with an arbitrary source impedance is presented and experimentally verified. This method allows for the determination of the minimum noise figure, NFmin, equivalent noise resistance, Rn, and optimum source admittance Yopt , of MOSFET directly from a single high-frequency 50-Omega noise figure measurement and a model characterization based on the transistor's measured scattering parameters. The proposed method can accurately predict the noise parameters of deep-submicron MOSFETs, and hence is useful in the design of low-noise radio-frequency integrated circuits (RFICs). Application of the proposed method in the design of CMOS RF low-noise amplifiers (LNAs) is also discussed 相似文献
15.
Shiming Zhang Guofu Niu Cressler J.D. Joseph A.J. Freeman G. Harame D.L. 《Electron Devices, IEEE Transactions on》2002,49(3):429-435
We examine the geometrical scaling issues in SiGe HBT technology. Width Scaling, length scaling, and stripe-number scaling are quantified from a radio frequency (RF) design perspective at 2 GHz. We conclude that a SiGe HBT with emitter area AE=0.5×20×6 μm2 is optimum for low noise applications at Jc=0.1 mA/μm2 and f=2 GHz using the design methodology, which guarantees optimal noise and input impedance matching with the simplest matching network. Finally, the optimal device sizes at f=4 and 6 GHz for low noise applications are also obtained using the same method 相似文献
16.
These devices have a planar structure with the channel and gate regions formed by the selective implantation of silicon and beryllium into an Fe-doped semi-insulating InP substrate. The nominal gate length is 2 μm with a channel doping of 1017 cm-3 and thickness of 0.2 μm. The measured values of f T and f max are 10 and 23 GHz, respectively. Examination of the equivalent circuit parameters and their variation with bias led to the following conclusions: (a) a relatively gradual channel profile results in lower than desired transconductance, but also lower gate-to-channel capacitance; (b) although for the present devices, the gate length and transconductance are the primary performance-limiting parameters, the gate contact resistance also reduces the power gain significantly; (c) the output resistance appears lower than that of an equivalent GaAs MESFET, and requires a larger V DS to reach its maximum value; and (d) a dipole layer forms and decouples the gate from the drain with a strength that falls between that of previously reported GaAs MESFETs and InP MESFETs 相似文献
17.
Sabido D.J.M. Tabara M. Fong T.K. Kalman R.F. Kazovsky L.G. 《Lightwave Technology, Journal of》1994,12(11):1976-1985
We constructed an experimental linewidth-insensitive coherent analog optical link. The transmitter utilizes an external electro-optic amplitude modulator and a semiconductor laser. The receiver consists of a heterodyne front-end, a wideband filter, square law detector and narrowband lowpass filter. We performed experimental measurements and theoretical analyses of the spurious-free dynamic range (SFDR), link gain and noise figure for both the coherent AM and the direct detection links; we investigated the dependencies of the foregoing parameters on the received optical signal power, laser linewidth, IF bandwidth, and the laser relative intensity noise (RIN). By selecting a wide enough bandpass filter, we made the coherent AM link insensitive to laser linewidth. The coherent AM link exhibits a higher SFDR than the corresponding direct detection link when the received optical signal power is less than 85 μW. The noise figure for the coherent link is greater than that for the direct detection link under all conditions investigated. For received optical signal powers greater than 4 μW, the link gain for the direct detection link is greater than that for the coherent AM link. The following are the link parameters that have been achieved for the coherent AM link investigated: SFDR=88 dB·Hz2/3, link gain=-25 dB and noise figure=78 dB; this performance has been obtained with a received optical signal power of 85 μW, and a local oscillator power at the photodetector of 228 μW. The link performance can be further improved by auxiliary subsystems such as a balanced receiver and impedance matched transmitter and receiver ends; and/or by using better optical and electrical devices like higher power lasers, linearized optical modulators, low-noise and high gain RF amplifiers, and optical amplifiers, 相似文献
18.
Wunderlich S. Schmidl F. Dorrer L. Schneidewind H. Seidel P. 《Applied Superconductivity, IEEE Transactions on》1999,9(1):71-76
The sensor performance of galvanically coupled Y1Ba2Cu3O7-x (YBCO) dc SQUID gradiometers on 24° bicrystal substrates has been improved by thickness reduction in the region of the grain boundary Josephson junctions using ion beam etching. The prepared etching mask allows the reduction of the critical current by more than one order of magnitude while the SQUID inductance is slightly increased. This treatment shifts the SQUID parameter βL from values above 10 to the proposed optimum around 1. The authors observed with decreasing critical current and increasing normal resistance a reduced ICRN product with values between 300 and 400 μV at 150-nm film thickness changing to values near 150 μV at 50-nm film thickness. Despite this fact, the white flux noise level as well as the low-frequency noise is reduced. With their galvanically coupled 4×8 mm2 dc SQUID gradiometer the authors obtained a white noise level of 4.2 μΦ0/√Hz corresponding to a field gradient sensitivity of 430 fT/cm√Hz at 77 K after the trimming process 相似文献
19.
Chung T. Bank S.R. Epple J. Kuang-Chien Hsieh 《Electron Devices, IEEE Transactions on》2001,48(5):835-839
The DC current gain dependence of InGaP/GaAs heterojunction bipolar transistors (HBTs) on subcollector and etch-stop doping is examined. Samples of InGaP/GaAs HBTs having various combinations of subcollector doping and etch-stop doping are grown, and large area 60 μm×60 (μ) HBTs are then fabricated for DC characterization. It is found that the DC current gain has a strong dependence on the doping concentration in the subcollector and the subcollector etch-stop. Maximum gain is achieved when the subcollector is doped at 6~7×10 18 cm-3 while the subcollector etch-stop is doped either above 6×1018 cm-3 (current gain/sheet resistance ratio, β/Rb=0.435 at Ic=1 mA) or below 3.5×1017 cm-3 (β/Rb=0.426~0.438 at Ic=1 mA). The data show that it is not necessary to heavily dope the subcollector etch-stop to reduce the conduction barrier and to obtain high current gain. The high current gain obtained with the low InGaP etch-stop doping concentration is attributed to the reduction of the effective energy barrier thickness due to band bending at the heterojunction between the InGaP etch-stop and the GaAs subcollector. These results show that the β/Rb of InGaP/GaAs HBTs can improve as much as 69% with the optimized doping concentration in subcollector and subcollector etch-stop 相似文献
20.
Hanyu I. Asai S. Nunokawa M. Joshin K. Hirachi Y. Ohmura S. Aoki Y. Aigo T. 《Electronics letters》1988,24(21):1327-1328
A T-shaped quarter-micron gate structure composed of WSix /Ti/Pt/Au has been developed for low-noise AlGaAs/GaAs HEMTs. The gate resistance R g was reduced to 0.3 Ω for devices with 200 μm-wide gates despite using WSix, and the source resistance R s reached 0.28 Ω mm by minimising the source-gate distance using a self-alignment technique. This HEMT exhibited the lowest reported noise figure of 0.54 dB with an associated gain of 12.1 dB at 12 GHz 相似文献