共查询到20条相似文献,搜索用时 10 毫秒
1.
GaAsSb for heterojunction bipolar transistors 总被引:1,自引:0,他引:1
The advantages of using GaAsSb in heterojunction bipolar transistors (HBT) are discussed with emphasis on two recent experimental results in the AlGaAs/GaAsSb material system. The performances of a prototype n-p-n AlGaAs/GaAsSb/GaAs double HBT (DHBT) that exhibits stable current gain with maximum collector current density of 5×10 4 A/cm2, and a p-n-p AlGaAs/GaAs HBT with a superlattice GaAsSb emitter ohmic contact which has a specific contact resistivity of 5±1×10-7 Ω-cm2 across the sample, are examined 相似文献
2.
Reducing length scales in npn heterojunction bipolar transistors leads to unexpected changes in the fundamental limits of device performance. Very high p -type carrier concentrations in the base result in a reduced inelastic electron scattering rate. In addition, there exists a maximum base/collector bias above which ballistic collector transport is not possible, and correct scaling requires the n -type collector contact to be unusually heavily doped 相似文献
3.
The modeling of small-signal intermodulation distortion (IMD) in heterojunction bipolar transistors (HBTs) is examined. The authors show that IMD current generated in the exponential junction is partially canceled by IMD current generated in the junction capacitance, and that this phenomenon is largely responsible for the unusually good IMD performance of these devices. Thus, a nonlinear model of the HBT must characterize both nonlinearities accurately. Finally, the authors propose a nonlinear HBT model suitable for IDM calculations, show how to measure its parameters, and verify its accuracy experimentally 相似文献
4.
Submicron InP-InGaAs-based single heterojunction bipolar transistors (SHBTs) are fabricated to achieve record-breaking speed performance using an aggressively scaled epitaxial structure coupled with a submicron emitter process. SHBTs with dimensions of 0.35 /spl times/16 /spl mu/m have demonstrated a maximum current gain cutoff frequency f/sub T/ of 377 GHz with a simultaneous maximum power gain cutoff frequency f/sub MAX/ of 230 GHz at the current density Jc of 650 kA/cm/sup 2/. Typical BV/sub CEO/ values exceed 3.7 V. 相似文献
5.
Patton G.L. Harame D.L. Stork J.M.C. Meyerson B.S. Scilla G.J. Ganin E. 《Electron Device Letters, IEEE》1989,10(12):534-536
Si/Si1-xGex heterojunction bipolar transistors (HBTs) fabricated using a low-temperature epitaxial technique to form the SiGe graded-bandgap base layer are discussed. These devices were fabricated on patterned substrates and subjected to annealing cycles used in advanced bipolar processing. These devices, which have base widths under 75 mm, were found to have excellent junction qualities. Due to the small bandgap of SiGe, the collector current at low bias is ten times higher than that for Si-base devices that have a pinched base resistance. This collector current ratio increases to more than 40 at LN2 temperature resulting in current gains of 1600 for the SiGe-base transistors despite base sheet resistances as low as 7.5 kΩ/□ 相似文献
6.
Mishra U.K. Jensen J.F. Rensch D.B. Brown A.S. Stanchina W.E. Trew R.J. Pierce M.W. Kargodorian T.V. 《Electron Device Letters, IEEE》1989,10(10):467-469
AlInAs-GaInAs heterojunction bipolar transistors (HBTs) and static flip-flop frequency dividers have been fabricated. An f t and an f max of 49 and 62 GHz, respectively, have been achieved in a device with a 2×5-μm2 emitter. Current-mode logic (CML) was used to implement static divide-by-two and divide-by-four circuits. The divide-by-two circuit operated at 15 GHz with 82-mW power dissipation for the single flip-flop. The divide-by-four circuit operated at 14.5 GHz with a total chip power dissipation of 444 mW 相似文献
7.
《Solid-state electronics》1987,30(11):1171-1173
Experimental approaches for measurement of the emitter injection efficiency in heterojunction bipolar transistors are discussed. The electron and hole currents crossing the base-emitter junction and the currents recombining within the quasi-neutral emitter and base region are also determined. The influence of the interface and space-charge region recombination is discussed qualitatively. New figures of merit for a bipolar transistor are introduced. Preliminary experimental results obtained on AlGaAs/GaAs transistors are presented. 相似文献
8.
Pseudomorphic AlInP/InP heterojunction bipolar transistors 总被引:1,自引:0,他引:1
Hsin Y.M. Ho M.C. Mei X.B. Liao H.H. Chin T.P. Tu C.W. Asbeck P.M. 《Electronics letters》1995,31(2):141-142
Novel InP-based heterojunction bipolar transistors (HBTs) using an AlInP pseudomorphic emitter, together with an InP base and collector, have been fabricated. By using InP as both base and collector, the advantage of high electron velocity and high breakdown field of InP collectors are obtained without the problem associated with the energy barrier between the more standard InGaAs/InP base and collector heterojunction. Epitaxial layers were grown by gas-source molecular beam epitaxy (GSMBE). The 200 Å pseudomorphic emitter had an aluminium fraction of 15%, sufficiently suppressing hole injection from the base. The DC gain for 40×40 μm2 devices reached 18. The breakdown voltage BVCEO of 10 V is an improvement over devices with InGaAs base and collector layers 相似文献
9.
The buried-layer technology was applied to the fabrication of high-speed p-n-p AlGaAs/GaAs heterojunction bipolar transistors (HBTs). The subcollector layer was selectively implanted prior to the epitaxial growth of the rest of the device structure thereby eliminating the need for deep mesa isolation. Devices with 2×10-μm2 emitter fingers and 100-nm base thickness had common-emitter current gains of 15 and cutoff frequencies of 17 GHz 相似文献
10.
Very-high-performance common-emitter InP/InGaAs single heterojunction bipolar transistors (HBTs) grown by metalorganic molecular beam epitaxy (MOMBE) are reported. They exhibit a maximum oscillation frequency (f T) of 180 GHz at a current density of 1×105 A/cm2. this corresponds to an (R BC BC)eff=f T/(8πf 2max) delay time of 0.12 ps, which is the smallest value every reported for common-emitter InP/InGaAs HBTs. The devices have 11 μm2 total emitter area and exhibit current gain values up to 100 at zero base-collector bias voltage. The breakdown voltage of these devices is high with measured BV CEO and BV CEO of 8 and 17 V, respectively 相似文献
11.
A theory of base transport in an abrupt-junction heterostructure bipolar transistor (HBT) is developed in the diffusion limit. The theory is valid for a continuous range of emitter injection energies Δ and accounts for the Early effect in both the static and the high-frequency limits. Small-signal network parameters strongly depend on Δ and differ from those in a graded emitter-base junction HBT 相似文献
12.
Jong-In Song Hong B.W.-P. Palmstrom C.J. Van Der Gaag B.P. Chough K.B. 《Electron Device Letters, IEEE》1994,15(3):94-96
We report on the microwave performance of InP/In0.53Ga 0.47As heterojunction bipolar transistors (HBT's) utilizing a carbon-doped base grown by chemical beam epitaxy (CBE). The fT and fmax of the HBT having two 1.5×10 μm2 emitter fingers were 175 GHz and 70 GHz, respectively, at IC=40 mA and VCE=1.5 V. To our knowledge, the f T of this device is the highest of any type of bipolar transistors yet reported. These results indicate the great potential of carbon-doped base InP/InGaAs HBT's for high-speed applications 相似文献
13.
InAlAs/InGaAs heterojunction bipolar transistors fabricated from wafers grown by molecular beam epitaxy are discussed. A cutoff frequency of 32 GHz for a collector current of 20 mA is achieved in the emitter area of devices 6×10 μm2. The use of heavily doped and nondoped InGaAs layers as the emitter cap and collector, respectively, results in a reduction of the emitter and collector charging times; this, in turn, leads to improved microwave performance 相似文献
14.
《Electron Device Letters, IEEE》1987,8(10):472-474
It is shown that in emitter-down heterojunction bipolar transistors (HBT's), parasitics can be reduced sufficiently that intrinsic transit-time delays become the dominant limitations to high-frequency performance. In this situation it is found that the dependence of the unilateral gain on frequency can be significantly different from the simple 6-dB/octave decrease usually assumed. It is found that the device exhibits negative output conductance over certain bands of frequencies, and that when this occurs a series of resonances are observed in the gain versus frequency characteristics. Explanations of this behavior are given in terms of the phase delay of the common-base current gain. The generality and relevance of these observations to other types of transistors, and the utilization of the negative output conductance to enhance high-frequency operation are also discussed. 相似文献
15.
The Early voltage for abrupt double heterojunction bipolar transistors (DHBTs) has been calculated by using an effective junction velocity (Sc) at the base-collector heterojunction. Sc is obtained by self-consistently partitioning thermionic and quantum mechanical tunneling currents. Unlike single heterojunction bipolar transistors (SHBTs), the Early voltage varies very rapidly at low reverse bias and approaches the SHBT-limit at sufficiently high reverse bias. This is attributed to the presence of an energy barrier at the b-c heterojunction 相似文献
16.
GaAlAs-GaAs heterojunction bipolar transistors (HBTs) with an abrupt emitter-base interface have been realised by molecular-beam epitaxy (MBE) on semi-insulating substrates. A gain-bandwidth product FT of 15 GHz has been measured for Ic = 20 mA and VCE = 8 V. These results are the best reported so far for HBTs and are very promising for high-speed logic. 相似文献
17.
We have previously analyzed the collapse phenomenon in heterojunction bipolar transistors (HBT's) when the mutual couplings among the transistor fingers are negligible. In this investigation, we derive the collapse loci equations in 2-finger HBT's in the presence of thermal coupling. It is found that the collapse loci equations are closely linked to a thermal instability condition best determined from the transistor regression characteristics. Unlike the previous derivation assuming zero thermal coupling, the collapse loci equations derived here are different depending on whether the HBT is driven by constant base current or constant base voltage bias 相似文献
18.
《Electron Device Letters, IEEE》1985,6(12):648-651
The performance of P-n-p AlGaAs/GaAs heterojunction microwave and switching transistors is compared to that of N-p-n structures. The maximum frequency of oscillation calculated for an optimized P-n-p microwave transistor is found to be only 29 percent less than that for an optimized N-p-n device. Similarly, the switching time of a P-n-p in a digital circuit is found to be only 28 percent greater than that of an N-p-n. These results are explained in terms of the parameters of a compact transistor model. The potential for use of the P-n-p HBT in microwave and switching applications is discussed in light of both performance and fabrication details. 相似文献
19.
General expressions for the h parameters of small-signal equivalent circuit models for emitter-up and emitter-down heterojunction bipolar transistors (HBTs) are derived. The unilateral gain U is calculated from these h parameters for InGaAs/InAlAs n-p-n HBTs. When the device parasitics are sufficiently reduced, the unilateral gain is found to exhibit a resonance behavior at high frequencies that deviates from the traditionally assumed 6-dB/octave roll-off. This unusual behavior in the unilateral gain is found to be caused by the appearance of negative output conductance of the device in certain bands of frequencies. The occurrence of the negative output conductance is shown to be a transit-time effect, and its implication for the device performance at high frequencies is discussed 相似文献
20.
Patton G.L. Iyer S.S. Delage S.L. Tiwari S. Stork J.M.C. 《Electron Device Letters, IEEE》1988,9(4):165-167
The devices were fabricated using molecular-beam epitaxy (MBE), low-temperature processing, and germanium concentrations of 0, 6%, and 12%. The transistors demonstrate current gain, and show the expected increase in collector current as a result of reduced bandgap due to Ge incorporation in the base. For a 1000-Å base device containing 12% Ge, a six-times increase in collector current was measured at room temperature, while a 1000-times increase was observed to 90 K. The temperature dependence of the collector current of the Si0.88Ge0.12 base transistor is consistent with a bandgap shrinkage in the base of 50 meV. For the homojunction transistors, base widths as thin as 800 Å were grown, corresponding to a neutral base width of no more than 400 Å 相似文献