共查询到20条相似文献,搜索用时 46 毫秒
1.
An anisotype heterojunction field-effect transistor (A-HJFET) for GaAs digital integrated circuit applications is proposed. A thin, highly doped, strained InxGa1-xAs (x ⩽0.2) n-channel is employed for improved transconductance while a p+-GaAs cap is used to enhance the dynamic gate voltage range of the device. Prototype devices with 5-μm gate lengths show a maximum transconductance of 80 mS/mm at V ds=2 V and a forward gate bias voltage of up to +2 V without significant leakage current 相似文献
2.
Nguyen L.D. Schaff W.J. Tasker P.J. Lepore A.N. Palmateer L.F. Foisy M.C. Eastman L.F. 《Electron Devices, IEEE Transactions on》1988,35(2):139-144
The authors describe a study of charge control in conjunction with DC and RF performance of 0.35-μm-gate-length pseudomorphic AlGaAs/InGaAs MODFETs. Using C -V measurements, they estimate that a two-dimensional electron gas (2DEG) with density as high as 1.0×1012 cm-2 can be accumulated in the InGaAs channel at 77 K before the gate begins to modulate parasitic charges in the AlGaAs. This improvement in charge control of about 10-30% over a typical AlGaAs/GaAs MODFET may partially be responsible for the superior DC and RF performance of the AlGaAs/InGaAs MODFET. At room temperature, the devices give a maximum DC voltage gain g m/g d of 32 and a current gain cutoff frequency f T of 46 GHz. These results are state of the art for MODFETs of similar gate length 相似文献
3.
Linga K.R. Olsen G.H. Ban V.S. Joshi A.N. Kosonocky W.F. 《Lightwave Technology, Journal of》1992,10(8):1050-1055
The dark current properties of InxGa1-xAs photodiodes, where x is varied from 0.53 to 0.82 for extending the long wavelength cutoff from 1.7 to 2.6 μm, are described. Detailed analyses of optoelectrical parameters of In0.82Ga 0.1As photodiodes are presented. Dark current, which is a critical parameter and limits the operation of the photodiode, is analyzed and compared with the experimental values. Typical characteristics of photodiodes with cutoff wavelengths of 1.7 μm (x =0.53), 2.2 μm (x =0.72), and 2.6 μm (x =0.82) are presented. The typical and best values of the dark currents obtained are presented 相似文献
4.
Laskar J. Ketterson A.A. Baillargeon J.N. Brock T. Adesida I. Cheng K.Y. Kolodzey J. 《Electron Device Letters, IEEE》1989,10(12):528-530
The observation of negative differential resistance (NDR) and negative transconductance at high drain and gate fields in depletion-mode AlGaAs/InGaAs/GaAs MODFETs with gate lengths L g ~0.25 μm is discussed. It is shown that under high bias voltage conditions, V ds>2.5 V and V gs>0 V, the device drain current characteristic switches from a high current state to a low current state, resulting in reflection gain in the drain circuit of the MODFET. The decrease in the drain current of the device corresponds to a sudden increase in the gate current. It is shown that the device can be operated in two regions: (1) standard MODFET operation for V gs<0 V resulting in f max values of >120 GHz, and (2) a NDR region which yields operation as a reflection gain amplifier for V gs >0 V and V ds>2.5 V, resulting in 2 dB of reflection gain at 26.5 GHz. The NDR is attributed to the redistribution of charge and voltage in the channel caused by electrons crossing the heterobarrier under high-field conditions. The NDR gain regime, which is controllable by gate and drain voltages, is a new operating mode for MODFETs under high bias conditions 相似文献
5.
A high-transconductance n-channel, depletion-mode InGaAs metal-semiconductor field-effect transistor (MESFET) with a Langmuir-Blodgett deposited gate fabricated on organometallic chemical vapor deposition (OMCVD)-grown InGaAs lattice matched to InP is reported. The fabrication process is similar to epitaxial GaAs FET technology and is suitable for making optoelectronic integrated circuits (OEICs) for long-wavelength fiber-optic communications systems. Devices with 1-μm gate and 6×1016 channel doping achieved 162-mS/mm extrinsic transconductance and -1.8-V pinch-off voltage. The effective saturation velocity of electrons in the channel was measured to be between 3.5 and 3.9×107 cm/s. The drain current ( I dss), 300 mA/mm at V ds=2.5 V, is the highest current capability reported for depletion-mode InGaAs MESFET devices with low pinch-off voltages 相似文献
6.
pin photodiodes with a 2.3 μm absorption edge are presented, using hydride vapour phase epitaxy. A Ga1-yInyAs (y =0.72) absorption layer, lattice-mismatched to the InP substrate, was grown on an InAsxP1-x (x =0-0.33) graded composition buffer layer. Typical dark current was 5 μA (0.03 A/cm2) at -6 V. Effective carrier lifetime of 0.05 μs was estimated from I/V characteristics 相似文献
7.
The authors achieved the first high responsitivity R v=30000 V/W, high detectivity D *=1×1010 cm √(Hz)/W GaAs/AlGaAs multiquantum-well superlattice detector which is sensitive in the long wavelength infra-red (LWIR) spectral region. This detector operates at λ=8.3 μm and at a temperature of T =77 K 相似文献
8.
Chough K.B. Chang T.Y. Feuer M.D. Sauer N.J. Lalevic B. 《Electron Device Letters, IEEE》1992,13(9):451-453
Record high f TL g products of 57 and 46 GHz-μm have been achieved in Ga1-x Inx As/AlInAs MODFETs with a strain compensated channel of x =0.77 and a lattice-matched channel of x =0.53, respectively. Although gm as high as 950 mS/mm has been obtained by conventional deep recess for the gate, these latter devices show a prominent kink effect which lowers f T and the voltage gain. By limiting the depth of final nonselective recess etch to 3 nm with the help of selective step etches, f T as high as 47 GHz and gm as high as 843 mS/mm have been achieved for MODFETs with x =0.77 and L g=1.1 μm 相似文献
9.
The authors report on advanced ion implantation GaAs MESFET technology using a 0.25-μm `T ' gate for super-low-noise microwave and millimeter-wave IC applications. The 0.25×200-μm-gate GaAs MESFETs achieved 0.56-dB noise figure with 13.1-dB associated gain at 50% I DSS and 0.6 dB noise figure with 16.5-dB associated gain at 100% I DSS at a measured frequency of 10 GHz. The measured noise figure is comparable to the best noise performance of AlGaAs/GaAs HEMTs and AlGaAs/InGaAs/GaAs pseudomorphic HEMTs 相似文献
10.
Kiely P.A. Vang T.A. Micovic M. Lepore A. Taylor G.W. Malik R. Docter D.P. Evaldsson P.A. Claisse P.R. Brown-Goebeler K.F. Storz F. 《Electronics letters》1994,30(6):529-531
The scaling to 0.5 μm of the inversion channel HFET with a single strained InGaAs quantum well is described. A unity current gain frequency of 40 GHz, gm=205 mS/mm and VTH=-0.34 V have been obtained for 0.5×100 μm2 devices. For shorter gate lengths, threshold shifts are sizeable so that in order to scale further, modifications to the growth and processing are required 相似文献
11.
Mesquida Kusters A. Kohl A. Muller R. Sommer V. Heime K. 《Electron Device Letters, IEEE》1993,14(1):36-39
The design and fabrication using low-pressure metalorganic vapor phase epitaxy (LP-MOVPE) of a HEMT on InP substrate that only uses InP and InxGa1-xAs as layer materials are reported. Lattice-matched (x =0.53) and strained (x =0.68) channels and a double-heterojunction design were used in this investigation. The DC performance of the 0.8-μm devices at 300 and 77 K was excellent for both cases. Improvements of 9 and 22% in g mext with the strain were measured at the same temperatures, in accordance with theoretical predictions. The approach described may serve as a very useful alternative, especially in MOVPE growth, to InAlAs containing structures because it eliminates many of the troublesome effects such as kinks, deep levels, interface states, high output conductances, and gate leakage, which are to a large extent attributed to impurity-Al interactions. The use of lattice-mismatched InGaAs as channel layer increases the conduction band offset to InP, the DH structure improves both confinement and current, and the p-InP barrier layer results in sufficiently high quasi-Schottky barriers 相似文献
12.
Double quantum-well modulation-doped field-effect transistors (MODFETs) with planar-doped lattice-strained AlGaAs/InGaAs structure have been fabricated and characterized at DC and microwave frequencies. At 300 K the 0.3-μm gate devices show a full channel current of 1100 mA/mm with a constant extrinsic transconductance of 350 mS/mm over a broad gate voltage range of 1.6 V. Excellent microwave performance is also achieved with a maximum available gain cutoff frequency f mag of 110 GHz and a current gain cutoff frequency f r of 52 GHz. A maximum output power of 0.7 W/mm with 30% efficiency is obtained at 18 GHz 相似文献
13.
Kurtz S.R. Dawson L.R. Biefeld R.M. Fritz I.J. Zipperian T.E. 《Electron Device Letters, IEEE》1989,10(4):150-152
Long-wavelength infrared photodiodes were fabricated using InAs 1-xSbx/InSb (x =0.82-0.85) strained-layer superlattices (SLSs). These structures can be grown using either molecular-beam epitaxy or metalorganic chemical vapor deposition. These photodiodes display broad spectral responses up to wavelengths greater than or approximately equal to 10 μm, and detectivities of 1×10 9 cm-Hz1/2/W at 10 μm 相似文献
14.
GaAs/AlGaAs Pnp heterojunction bipolar transistors (HBTs) were fabricated and tested on (100) Si substrates for the first time. A common-emitter current gain of β=8 was measured for the typical devices with an emitter area of 50×50 μm2 at a collector current density of 1×104 A/cm2 with no output negative differential resistance up to 280 mA, highest current used. A very high base-collector breakdown voltage of 10 V was obtained. Comparing the similar structures grown on GaAs substrates, the measured characteristics clearly demonstrate that device grade hole injection can be obtained in GaAs on Si epitaxial layers despite the presence of dislocations 相似文献
15.
Liu C.-T. Yu C.-H.D. Kornblit A. Lee K.-H. 《Electron Devices, IEEE Transactions on》1992,39(12):2803-2809
The I -V characteristics of inverted thin-film transistors (TFT) are studied. A simple lightly doped drain (LDD) structure is utilized to control the channel electric field at the drain junction and to improve the performance of the TFTs. The LDD region is self-aligned to the channel and the source/drain regions. It is created by a spacer around an oxide mask which exclusively defines the channel length L ch. Experimental data show that the leakage current, subthreshold swing SS, saturation current, and on/off current ratio of the inverted TFTs are closed related to L ch, L LDD, the drain bias, gate voltage, and LDD dose. With a gate deposited at low temperature, a saturation current of ~1.25 μA at 5 V and a leakage current of ~0.03 pA per micrometer of channel width were achieved. The current ratio therefore exceeds seven orders of magnitude, with an SS of 380 mV/decade. At 3.3 V, the current ratio is ~7×106 相似文献
16.
An In0.41Al0.59As/n+-In0.65 Ga0.35As HFET on InP was designed and fabricated, using the following methodology to enhance device breakdown: a quantum-well channel to introduce electron quantization and increase the effective channel bandgap, a strained In0.41Al0.59As insulator, and the elimination of parasitic mesa-sidewall gate leakage. The In0.65Ga0.35As channel is optimally doped to N D=6×1018 cm-3. The resulting device (L g=1.9 μm, W g =200 μm) has f t=14.9 GHz, f max in the range of 85 to 101 GHz, MSG=17.6 dB at 12 GHz V B=12.8 V, and I D(max)=302 mA/mm. This structure offers the promise of high-voltage applications at high frequencies on InP 相似文献
17.
In an effort to enhance the conduction band discontinuity between channel and insulator, InxAl1-xAs/n+-In 0.53Ga0.47As heterostructure field-effect transistors (HFETs) were fabricated with InAs mole fractions in the In xAl1-xAs gate insulator of x =0.52 (lattice matching), 0.48, 0.40, and 0.30. Decreasing the InAs mole fraction in the insulator results in reduced forward- and reverse-bias gate currents, increased reverse gate breakdown voltage, and reduced real-space transfer of hot electrons from channel to gate. Down to x =0.40, these improvements trade off with a slightly reduced transconductance, but the gain in gate bias swing results in an increase in maximum current drivability. From x =0.40 to x =0.30, there is a drastic decrease in transconductance, coincident with a high density of misfit dislocations 相似文献
18.
A two-dimensional numerical analysis is presented to investigate the breakdown characteristics of single- and double-channel AlGaAs/GaAs HEMTs. The influence of the doped layer thickness and the thickness of an undoped i-layer under the gate is analyzed. Impact ionization is considered to be the dominant breakdown mechanism. All simulations reveal the existence of a high electric field region near the gate contact. Breakdown occurs in the gate-drain region and the (breakdown) path which maximizes the ionization integral is entirely in the AlGaAs layer. For increased donor layer thickness, single-channel devices biased near pinchoff have gate-drain breakdown voltages varying from 8 to 14 V with corresponding peak electric field values in the range of 8.2×105 to 2.4×106 V/cm. The breakdown voltage increases with increasing gate bias |V gs| due to a screening effect of transverse from longitudinal electric field. Double-channel HEMTs have slightly higher breakdown than single-channel, especially near pinchoff and for thin donor layers 相似文献
19.
Wu C.S. Wen C.P. Sato R.N. Hu M. Tu C.W. Zhang J. Flesner L.D. Pham L. Nayer P.S. 《Electron Devices, IEEE Transactions on》1992,39(2):234-241
The authors have demonstrated photovoltaic detection for a multiple-quantum-well (MQW) long-wavelength infrared (LWIR) detector. With a blocking layer, the MQW detector exhibits Schottky I -V characteristics with extremely low dark current and excellent ideality factor. The dark current is 5×10-14 A for a 100×100 μm2 detector (designed for 10-μm response) at 40 K, nearly nine orders of magnitude lower than that of a similar MQW LWIR detector without the blocking layer. The ideality factor is ~1.01-1.05 at T =40-80 K. The measured Schottky-barrier height is consistent with the energy difference between first excited states and ground states, or the peak of spectral response. The authors also report a measured effective Richardson constant (A **) for a GaAs/AlGaAs heterojunction using this blocking layer structure. The A ** is ~2.3 A/cm2/K 2 相似文献
20.
Nguyen L.D. Tasker P.J. Radulescu D.C. Eastman L.F. 《Electron Devices, IEEE Transactions on》1989,36(10):2243-2248
The authors report a detailed characterization of ultrahigh-speed pseudomorphic AlGaAs/InGaAs (on GaAs) modulation-doped field-effect transistors (MODFETs) with emphasis on the device switching characteristics. The nominal 0.1-μm gate-length device exhibit a current gain cutoff frequency (f t) as high as 152 GHz. This value of f t corresponds to a total delay of approximately 1.0 ps and is attributed to the optimization of layer structure, device layout, and fabrication process. It is shown that the electron transit time in these very short gate-length devices still accounts for approximately 60% of the total delay, and, as a result, significant improvements in switching speed are possible with further reductions of gate length. The results reported clearly demonstrate the potential of the pseudomorphic AlGaAs/InGaAs MODFET as an ultrahigh-speed device. Its excellent switching characteristics are attributed to the high saturation velocity (~2×107 cm/s), 2DEG sheet density (2.5×1012 cm-2), and current drive capability (>200 mA/mm at the peak transconductance) 相似文献