共查询到20条相似文献,搜索用时 31 毫秒
1.
InAlAs-InGaAs HEMTs with 0.4- to 5-μm gate lengths have been fabricated and a maximum f T of 84 GHz has been obtained by a device with a 0.4-μm gate length. A simple analysis of their delay times was performed. It was found that gradual channel approximation with a field-dependent mobility model with E c of 5 kV/cm holds for long-channel devices (L g>2 μm), while a saturated velocity model with a saturated velocity of 2.7×107 cm/s holds for short-channel devices (L g<1 μm) 相似文献
2.
Magneto-transport and cyclotron resonance measurements were made to determine directly the density, mobility, and the effective mass of the charge carriers in a high-performance 0.15-μm gate In0.52 Al0.48As/In0.53Ga0.47As high-electron-mobility transistor (HEMT) at low temperatures. At the gate voltage V G=0 V, the carrier density n g under the gate is 9×1011 cm-2, while outside of the gate region n g=2.1×1012 cm-2. The mobility under the gate at 4.2 K is as low as 400 cm2/V-s when V G<0.1 V and rapidly approaches 11000 cm2/V-s when V G>0.1 V. The existence of this high mobility threshold is crucial to the operation of the device and sets its high-performance region in V G>0.1 V 相似文献
3.
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
4.
A study of the high-frequency performance of short-gate ion-implanted GaAs MESFETs with gate lengths of 0.3 and 0.5 μm is discussed. Excellent DC and microwave performance have been achieved with an emphasis on the reduction of effective gate length during device fabrication. From f t of 83 and 48 GHz for 0.3-0.5-μm gate devices, respectively, an electron velocity of 1.5×107 cm/s is estimated. An f t of 240 GHz is also projected for a 0.1-μm-gate GaAs MESFET. These experimental results are believed to be comparable to those of the best HEMTs (high-electron-mobility transistors) reported and higher than those generally accepted for MESFETs 相似文献
5.
High-performance submicrometer undergated thin-film transistors (TFTs) are fabricated without using high-temperature rapid thermal annealing or plasma hydrogenation. These processes are used in the state-of-the-art devices, but avoided in current manufacturing. For a 0.35-μm×0.35-μm device and a 0.7-μm×0.5-μm device, I ON of 3 and 1.2 μA are obtained with ON/OFF current ratios of 4×105 and 1.2×108 , respectively, very close to that of state-of-the-art devices. A new lightly-doped-drain (LDD) structure is employed to improve I ON reproducibility, which is difficult to achieve for deep-submicrometer devices with the conventional lightly-doped-offset (LDO) structure 相似文献
6.
Chen Y.-K. Temkin H. Tanbun-Ek T. Logan R.A. Nottenburg R.N. 《Electron Device Letters, IEEE》1989,10(4):162-164
Buried p-buffer double heterostructure modulation-doped field-effect transistors (BP DH-MODFETs) with an InGaAs quantum-well channel were fabricated with high transconductance and good breakdown voltage, by placing the metal gate directly on Fe-doped InP insulating layer. Excellent extrinsic DC transconductance of 560 mS/mm and a high gate-to-drain diode breakdown voltage (greater than 20 V) were achieved at room temperature with FETs of 1.2-μm gate length. Unity currently gain cutoff frequency f T of 24 GHz and maximum oscillation frequency f max of 60 GHz were demonstrated for a drain to source voltage V DS=4 V, which corresponds to an average electron velocity of 2.2×107 cm/s in the quantum well 相似文献
7.
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
8.
《Electron Devices, IEEE Transactions on》1990,37(1):153-158
The fabrication of a silicon heterojunction microwave bipolar transistor with an n+ a-Si:H emitter is discussed, and experimental results are given. The device provides a base sheet resistance of 2 kΩ/□ a base width 0.1 μm, a maximum current gain of 21 (V CE=6 V, I c=15 mA), and an emitter Gummel number G E of about 1.4×1014 Scm-4. From the measured S parameters, a cutoff frequency f t of 5.5 GHz and maximum oscillating frequency f max of 7.5 GHz at V CE=10 V, I c=10 mA are obtained 相似文献
9.
Hayden J.D. Mele T.C. Perera A.H. Burnett D. Walczyk F.W. Lage C.S. Baker F.K. Woo M. Paulson W. Lien M. See Y.-C. Denning D. Cosentino S.J. 《Electron Devices, IEEE Transactions on》1992,39(7):1669-1679
A high-performance 0.5-μm BiCMOS technology has been developed. Three layers of polysilicon are used to achieve a compact four-transistor SRAM bit cell size of less than 20 μm2 by creating self-aligned bit-sense and V ss contacts. A WSix polycide emitter n-p-n transistor with an emitter area of 0.8×2.4 μm2 provides a peak cutoff frequency (f T) of 14 GHz with a collector-emitter breakdown voltage (BV CFO) of 6.5 V. A selectively ion-implanted collector (SIC) is used to compensate the base channeling tail in order to increase f T and knee current without significantly affecting collector-substrate capacitance. ECL gate delays as fast as 105 ps can be obtained with this process 相似文献
10.
Channel hot-electron-generated substrate currents were measured in MOSFET devices with channel lengths down to 0.09 μm, and a family of characteristic plots of substrate current, normalized to drain current, I SUB/I D, rather than (V DS-V DSAT)-1 was obtained. For channel lengths greater than 0.5 μm, the characteristics are independent of channel length. For channel lengths in the range of 0.15 μm, the characteristics are independent of channel length. For channel lengths in the range of 0.15 μm, the normalized substrate current at constant V DS increases with decreasing channel length. However, as the channel length is decreased below 0.15 μm, a decrease of the normalized substrate current is observed. The decrease is larger at 77 K than at 300 K. This decrease accompanies the onset of electron velocity overshoot over a large portion of the channel. It is suggested that the decrease is due either to a decrease of carrier energy because energy relaxation and transit times become comparable, to a relative decrease of the carrier population in the channel, or to both 相似文献
11.
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
12.
Noda M. Hosogi K. Oku T. Nishitani K. Otsubo M. 《Electron Devices, IEEE Transactions on》1992,39(4):757-766
The authors present formation conditions for ion-implanted regions of a GaAs buried p-layer lightly doped drain (BPLDD) MESFET that can improve short-channel effect, V th uniformity, and FET operating speed, simultaneously. For 0.7-μm gates, a Mg+ dose of 2×1012 cm-2 at 300 keV and a Si+ dose of 2×1012 cm-2 at 50 keV are suitable for the p layer and n' layer, respectively. A σV th of 7 mV is realized. Gate-edge capacitance of the 0.7-μm-gate BPLDD that consists of both overlap capacitance and fringing capacitance is successfully reduced to 0.5 fF/μm, which is about 50% of that of a non-LDD buried p-layer (BP) FET. Another parasitic capacitance due to the p-layer was found to have less effect on the speed than the gate-edge one. Consequently, the gate propagation delay time of the BPLDD can be reduced to 15 ps at power dissipation of 1 mW/gate, which is about 65% of that of a BP. Applying the 0.7-μm-gate BPLDD to 16-kb SRAMs, the authors have obtained a maximum access time of less than 5 ns with a galloping test pattern 相似文献
13.
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
14.
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
15.
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
16.
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
17.
Kabza H. Ehinger K. Meister T.F. Meul H.-W. Weger P. Kerner I. Miura-Mattausch M. Schreiter R. Hartwig D. Reisch M. Ohnemus M. Kopl R. Weng J. Klose H. Schaber H. Treitinger L. 《Electron Device Letters, IEEE》1989,10(8):344-346
A double-poly-Si self-aligning bipolar process employing 1-μm lithography is developed for very-high-speed circuit applications. Epilayer doping and thickness are optimized for breakdown voltages and good speed-power performance. Shallow base-emitter profiles are obtained by combining low-energy boron implantation and rapid thermal annealing (RTA) for the emitter drive-in. A transit frequency f T =14 GHz at V BC=-1 V and a current-mode-logic (CML) gate delay of 43 ps at 30 fJ are achieved. For an emitter size of 1.0×2.0 μm2 a minimum power-delay product of 15 fJ is calculated. Circuit performance capability is demonstrated by a static frequency divider operating up to 15 GHz 相似文献
18.
A theoretical investigation of Si/Si1-xGex heterojunction bipolar transistors (HBTs) undertaken in an attempt to determine their speed potential is discussed. The analysis is based on a compact transistor model, and devices with self-aligned geometry, including both extrinsic and intrinsic parameters, are considered. For an emitter area of 1×5 μm2, an f t of over 75 GHz and f max of over 35 GHz were computed at a collector current density of 1×10 5 A/cm2 and V CB of 5 V 相似文献
19.
Hori A. Segawa M. Kameyama S. Yasuhira M. 《Electron Devices, IEEE Transactions on》1993,40(9):1675-1681
A self-aligned pocket implantation (SPI) technology is discussed. This technology features a localized pocket implantation using the gate and drain electrodes (TiSi2 film) as well as self-aligned masks. The gate polysilicon is patterned by KrF excimer laser lithography. The measured minimum gate length L g (the physical gate length) is 0.21 μm for both N- and P-MOSFETs. A newly developed photoresist was used to achieve less than quarter-micrometer patterns. This process provides high punchthrough resistance and high current driving capability even in such a short channel length. The subthreshold slope of the 0.21-μm gate length is 76 mV/dec for N-MOSFETs and 83 mV/dec for P-MOSFETs. The SPI technology maintains a low impurity concentration in the well (less than 5×10 16 cm-3). The drain junction capacitance is decreased by 36% for N-MOSFETs and by 41% for P-MOSFETs, compared to conventional LDD devices, which results in high-speed circuit operation. The delay time per stage of a 51-stage dual-gate CMOS ring oscillator is 50 ps with a supply voltage of 3.3 V and a gate length of 0.36 μm, and 40 ps with a supply voltage of 2.5 V and a gate length of 0.21 μm 相似文献
20.
The characteristics of polycrystalline silicon thin-film transistors (poly-Si TFTs) with a field-induction-drain (FID) structure using an inversion layer as a drain are investigated. The FID structure not only reduces the anomalous leakage current, but also maintains a high on current. An off current of 1.5 pA/μm and an on/off current ratio of 107 (V d=10, V g =-20 V) are successfully obtained. These characteristics result from good junction characteristics between the p channel and n+ inversion layer. Reducing the threshold voltage of the FID region allows a simple circuit configuration for the FID TFTs 相似文献