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1.
A novel InGaP/GaAs0.94Sb0.06/GaAs double heterojunction bipolar transistor is presented. It features the use of fully strained pseudomorphic GaAs0.94Sb0.06 as the base layer and an InGaP layer as the emitter, which both eliminate misfit dislocations and current blocking, and increase the valence band discontinuity at the InGaP/GaAsSb interface. The device demonstrates a high current gain and a low turn-on voltage 相似文献
2.
Bolognesi C.R. Dvorak M.M.W. Yeo P. Xu X.G. Watkins S.P. 《Electron Devices, IEEE Transactions on》2001,48(11):2631-2639
We report on the physical operation and performance of MOCVD-grown abrupt heterojunction InP/GaAs0.51Sb0.49/InP double heterojunction bipolar transistors (DHBTs). In particular, the effect of the InP collector thickness on the breakdown voltage and on the current gain cutoff frequency is assessed and a fT of 106 GHz is reported for a DHBT with a 400 Å base and a 2000 Å InP collector with a BVCEO of 8 V. We show that InP/GaAsSb/InP DHBTs are characterized by a weak variation of fT as a function of temperature. Finally, we also demonstrate that high maximum oscillation frequencies fMAX>fT can be achieved in scaled high-speed InP/GaAsSb/InP DHBTs, and provide estimates of the maximum cutoff frequencies achievable for this emergent but promising material system. Recent results on improved structures validate our performance predictions with cutoff frequencies well beyond 200 GHz 相似文献
3.
设计并生长了一种新的InGaP/GaAs/InGaP DHBT结构材料,采用在基区和集电区之间插入n+-InGaP插入层结构,以解决InGaP/GaAs/InGaP DHBT集电结导带尖峰的电子阻挡效应问题。采用气态源分子束外延(GSMBE)技术,通过优化生长条件,获得了高质量外延材料,成功地生长出带有n+-InGaP插入层结构的GaAs基InGaP/GaAs/InGaP DHBT结构材料。采用常规的湿法腐蚀工艺,研制出发射极面积为100μm×100μm的新型结构InGaP/GaAs/InGaP DHBT器件。直流特性测试的结果表明,所设计的集电结带有n+-InGaP插入层的InGaP/GaAs/InGaP DHBT器件开启电压约为0.15V,反向击穿电压达到16V,与传统的单异质结InGaP/GaAs HBT相比,反向击穿电压提高了一倍,能够满足低损耗、较高功率器件与电路制作的要求。 相似文献
4.
Bolognesi C.R. Matine N. Dvorak R.W. Xu X.G. Hu J. Watkins S.P. 《Electron Device Letters, IEEE》1999,20(4):155-157
We have developed lattice-matched InP/GaAs0.51Sb0.49/InP NpN double heterojunction bipolar transistors (DHBTs) which take advantage of the staggered (“type II”) band lineup at InP/GaAs0.51Sb0.49 interfaces: in this system the GaAs0.51Sb0.49 base conduction band edge lies ~0.18 eV above the InP collector conduction band, thus enabling the implementation of InP collectors free of the current blocking effect encountered in conventional Ga0.47In0.53As base DHBTs. The structure results in very low collector current offset voltages, low emitter-base turn-on voltages, and very nearly ideal base and collector current characteristics with junction ideality factors of nB=1.05 and nc=1.00. InP/GaAs0.51Sb0.49/InP DHBTs appear well-suited to low-power applications, but can also be used in power applications by virtue of their InP collector. The symmetry of the transistor band structure also lends itself to the potential integration of collector-up and emitter-up devices 相似文献
5.
Combining a pseudomorphically strained (Ga,In)P emitter with a GaAs0.6Sb0.4 base effectively eliminates the emitter heterojunction type-II conduction band offset in InP/GaAsSb double heterojunction bipolar transistors (DHBTs). A peak fT of 436 GHz at JC = 10 mA/mum2, with BVCEO = 3.8 V, is achieved with 0.6 times 5 mum2 InP/GalnP/GaAsSb DHBTs with a 75-nm InP collector. Compared to a binary InP emitter, the (Ga,In)P emitter doubles the DC current gain from 166 to 338 for otherwise identical devices. These are the highest DC current gain and cutoff frequencies to date in uniform base GaAsSb DHBTs. The gain improvement reported here will greatly facilitate device design tradeoffs that are encountered while scaling InP/GaAsSb DHBTs toward higher frequencies by allowing higher base doping levels and smaller emitter geometries. 相似文献
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7.
Li-Chang Chou Yu-Ru Lin Cheng-Tien Wan Hao-Hsiung Lin 《Microelectronics Journal》2006,37(12):1511-1514
We report the GaAsSb bulk layers and GaAsSb/GaAs quantum wells (QWs) grown on (1 1 1)B GaAs substrates by gas source molecular beam epitaxy. We found that Sb composition in the GaAsSb epilayers is very sensitive to the substrate temperature. The composition drops from 0.35 to 0.16 as the substrate temperature increases from 450 to 550 °C. The [1 1 1]B-oriented GaAsSb epilayers show phase separation when the substrate temperature is lower than 525 °C. For a GaAsSb/GaAs multiple quantum wells (MQWs) structure composed of five periods of 5 nm GaAs0.73Sb0.27 QW and 30 nm GaAs barrier, the room temperature photoluminescence emission is located at 1255, 80 nm longer than the [1 0 0]-oriented sample with the same Sb composition. The peak wavelength shows significant blue shift as the excitation level increases, which evidences the type-II band alignment in this heterostructure. 相似文献
8.
Yamada M. Anan T. Tokutome K. Kamei A. Nishi K. Sugou S. 《Photonics Technology Letters, IEEE》2000,12(7):774-776
GaAsSb quantum-well (QW) edge-emitting lasers grown on GaAs substrates were demonstrated. The optical quality of the QW was improved by optimizing the growth conditions and introducing a multi-QW to increase the gain. As a result, 1.27-μm lasing of a GaAs0.66 Sb0.34-GaAs double-QW laser was obtained with a low-threshold current density of 440 A/cm2, which is comparable to that in conventional InP-based long-wavelength lasers. 1.30 μm lasing with a threshold current density of 770 A/cm2 was also obtained by increasing the antimony content to 0.36. GaAsSb QW was found to be a suitable material for use in the active layer of a 1.3-μm vertical-cavity surface-emitting lasers 相似文献
9.
A GaAs0.7Sb0.3/GaAs type-II quantum-well laser with a InAs quantum-dot (QD) layer adjacent to the well is reported. The laser shows much lower threshold current density, lower internal loss and higher characteristic temperature than the device without adjacent QDs. The better performances are attributed to additional dimensional confinement, resulting from a spatial potential fluctuation induced by the adjacent QDs, for carriers in the active region of the laser. 相似文献
10.
This paper identifies absorbers for multiple transition solar cells that are implemented with nanostructured heterojunctions [e.g., quantum well solar cells with quasi-Fermi-level variations and quantum dot (QD) intermediate-band solar cells]. In the radiative limit, the solar cells implemented with these absorbers are capable of achieving a conversion efficiency ges50% with a geometric solar concentration of at least 1000times. The technical approach enumerates a set of quantitative design rules and applies the rules to the technologically important III-V semiconductors and their ternary alloys. A novel design rule mandates a negligible valence band discontinuity between the barrier material and confined materials. Another key design rule stipulates that the substrate have a lattice constant in between that of the barrier material and that of the quantum-confined material, which permits strain compensation. Strain compensation, in turn, allows a large number of QD layers to be incorporated into the solar cell because each layer is free of defects. Four candidate materials systems (confined/barrier/substrate) are identified: InP0.85Sb0.15/GaAs/InP, InAs0.40P0.60/GaAs/InP, InAs/GaAs0.88Sb0.12/InP, and InP/GaAs0.70P0.30/GaAs. Resulting from the design features, the candidate systems may also find use in other optoelectronic applications. 相似文献
11.
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
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13.
DeLuca P.M. Lutz C.R. Welser R.E. Chi T.Y. Huang E.K. Welty R.J. Asbeck P.M. 《Electron Device Letters, IEEE》2002,23(10):582-584
InGaP/GaInAsN double heterojunction bipolar transistors (HBTs) with compositionally graded bases are presented which exhibit superior dc and radio frequency performance. Reducing the average base layer energy gap and optimizing the emitter-base (e-b) and base-collector (b-c) heterojunctions leads to a 100-mV reduction in the turn-on voltage compared to a baseline InGaP/GaAs process. Simultaneously grading the base layer energy band-gap results in over a 66% improvement in the dc current gain and up to a 35% increase in the unity gain cutoff frequency. DC current gains as high as 250 and cutoff frequencies of 70 GHz are demonstrated. In addition, the InGaP/GaInAsN DHBT structure significantly reduces the common emitter offset and knee voltages, as well as improves the dc current gain temperature stability relative to standard InGaP/GaAs HBTs. 相似文献
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We report on the dc and microwave performance of an MOCVD-grown carbon-doped GaInP/GaAs double heterojunction bipolar transistor (DHBT) with a thin highly doped n-type GaInP layer in the collector. The DHBT showed improved current-voltage characteristics at low collector-emitter bias compared with those of a DHBT without the heavily doped GaInP layer, while maintaining a high breakdown voltage (BVCEO~20 V). Small area, self-aligned emitter transistors with two 2×5 μm2 emitter fingers were fabricated and exhibited fT and fmax of 53 GHz and 75 GHz, respectively. These results indicate the promise of carbon-doped base GaInP/GaAs DHBT's for high-power microwave applications 相似文献
16.
具有AlGaAs缓变结构的InGaP/GaAs HBT性能改进分析 总被引:1,自引:0,他引:1
对改进型结构具有零导带势垒尖峰的缓变InGaP/AlGaAs/GaAs HBT器件的直流和高频特性进行了理论探讨,并同传统突变结构的InGaP/GaAs HBT的相应性能作了比较。结果表明:在低于30 nm的一定范围内的缓变层厚度下,与突变的InGaP/GaAs HBT相比,改进型结构的InGaP/AlGaAs/GaAs HBT具有更低的offset和开启电压、更强的电流驱动能力、更好的伏-安输出特性和高频特性。 相似文献
17.
During elevated-temperature bias stress, InGaP/GaAs HBT's grown by MOCVD show a medium-term degradation in current gain of about 20%, with an activation energy of 0.64 eV. They also show a corresponding decrease in base resistance and an increase in turn-on voltage. InGaP/GaAs HBTs grown by GSMBE, however, do not show this degradation. SIMS measurements show a five times greater than GSMBE-epi hydrogen concentration of about 1019 cm-3 in the base layer of the MOCVD-grown epi. The degradation can be explained by acceptor depassivation due to hydrogen out-diffusion from the epi during stress 相似文献
18.
The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO>6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs. 相似文献
19.
《Microelectronics Journal》2007,38(6-7):750-753
A novel InGaP/GaAs heterostructure-emitter bipolar transistor (HEBT) with InGaAs/GaAs superlattice-base structure is proposed and demonstrated by two-dimensional analysis. As compared with the traditional HEBT, the studied superlattice-base device exhibits a higher collector current, a higher current gain of 246, and a lower base–emitter (B–E) turn-on voltage of 0.966 V at a current level of 1 μA, attributed to the increased charge storage of minority carriers in the InGaAs/GaAs superlattice-base region by tunneling behavior. The low turn-on voltage can reduce the operating voltage and collector–emitter offset voltage for low power consumption in circuit applications. 相似文献
20.
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