共查询到20条相似文献,搜索用时 203 毫秒
1.
H. C. Kuo J. M. Kuo Y. C. Wang C. H. Lin H. Chen G. E. Stillman 《Journal of Electronic Materials》1997,26(8):944-948
We report the determination of band offset ratios, using photoluminescence excitation measurements, for GaInP/GaAs and AlInP/GaAs
quantum wells grown by gas-source molecular beam epitaxy. To reduce the uncertainty related to the intermixing layer at heterointerfaces,
the residual group-V source evacuation time was optimized for abrupt GalnP/GaAs (AlInP/GaAs) interfaces. Based upon thickness
and composition values determined by double-crystal x-ray diffraction simulation and cross-sectional transmission electron
microscopy, the transition energies of GalnP/GaAs and AlInP/GaAs quantum wells were calculated using a three-band Kane model
with varying band-offset ratios. The best fit of measured data to calculated transition energies suggests that the valence-band
offset ratio (γ band discontinuity) was 0.63 ± 0.05 for GalnP/GaAs and 0.54 ± 0.05 for AlInP/GaAs heterostructures. This result
showed good agreement with photoluminescence data, indicating that the value is independent of temperature. 相似文献
2.
The authors demonstrate excellent passivation of the extrinsic base surfaces in GaInP/GaAs heterojunction bipolar transistors (HBTs) having small emitter areas. Passivated devices with an area as small as 4×20 μm2 exhibit the highest reported current gain value of 2690 for GaInP/GaAs HBTs, while unpassivated 4×20-μm 2 devices exhibit a current gain of only 500. Measured current gains as a function of collector current density are almost identical for devices with varying emitter widths of 4, 6, 8, 12, 16, and 100 μm. The current gains are also nearly identical for devices with varying passivation ledge widths of 1, 2, 3, and 6 μm. These results are contrasted with those of a previously published study reporting surface passivation for a GaInP/GaAs HBT with a large emitter area 相似文献
3.
4.
C. S. Kyono B. Tadayon M. E. Twigg A. Giordana D. S. Simons M. Fatemi S. Tadayon 《Journal of Electronic Materials》1993,22(12):1437-1440
The effect of annealing on the electrical properties of a GaAs diode structure, which incorporated a nominally undoped low-temperature
(LT) layer on top of conventionally grown p-type GaAs, is examined. Unannealed GaAs grown by molecular beam epitaxy at substrate
temperatures below 250°C is amorphous and highly resistive. Annealing at high temperatures converts the undoped LT-GaAs from
amorphous to single crystal material. The annealed material is n-type. The current-voltage characteristics of the LT on p-type
GaAs structures showed greater asymmetry, with lower reverse leakage currents, as the anneal temperature was increased above
400°C. This reflects the improved crystal quality of the LT layer. 相似文献
5.
《Electron Devices, IEEE Transactions on》1987,34(2):224-229
The fabrication and characterization of MBE-grown AlGaAs/GaAs heterojunction bipolar transistors (HBT's) are described, A Be redistribution profile in the HBT epi-layer at the emitter-base heterojunction interface is investigated using secondary ion mass spectrometry, A relatively high substrate temperature of 650°C during growth can be employed by introducing a 100-Å undoped spacer layer between the emitter and base layer. A simple wafer characterization method using phototransistors is demonstrated for accurately predicting current gain in a three-terminal device. A dc current gain of up to 230 is obtained for the fabricated HBT with a heavy base doping of 1 × 1019/cm3. A gain-bandwidth product fT of 25 GHz is achieved with a 4.5-µm-width emitter HBT. 相似文献
6.
J. Garcia C. Dua S. Mohammadi J. W. Park D. Pavlidis 《Journal of Electronic Materials》1998,27(5):442-445
We report on the complete characterization of a hydride- and hydrogen-free chemical beam epitaxy (CBE) process for the realization
of GaAs/GaInP heterojunction bipolar transistors. Alternative group V sources tertiarybutylarsine, tertiarybutylphosphine,
and trisdimethylaminoarsenic are used instead of traditionally employed AsH3 and PH3. A very high degree of reproducibility of growth parameters (fluxes, substrate temperature, doping levels) is demonstrated.
Total defect densities lower than 10 def/cm2 are routinely obtained. Large-area GaInP/GaAs heterojunction bipolar transistors (HBTs) show a high current gain of 225 for
base sheet resistance of 400 ohm/sq. The devices also exhibit excellent high-frequency characteristics. A cut-off frequency
of 48 GHz and a maximum oscillation frequency of 60 GHz have been obtained. These results demonstrate the high potential capability
of CBE for high-throughput GaInP/GaAs HBT production. 相似文献
7.
Mochizuki K. Welty R.J. Asbeck P.M. Lutz C.R. Welser R.E. Whitney S.J. Pan N. 《Electron Devices, IEEE Transactions on》2000,47(12):2277-2283
This paper describes a novel heterojunction bipolar transistor (HBT) structure, the collector-up tunneling-collector HBT (C-up TC-HBT), that minimizes the offset voltage V/sub CE,sat/ and the knee voltage V/sub k/. In this device, a thin GaInP layer is used as a tunnel barrier at the base-collector (BC) junction to suppress hole injection into the collector, which results in small V/sub CE,sat/. Collector-up configuration is used because of the observed asymmetry of the band discontinuity between GaInP and GaAs depending on growth direction. To minimize V/sub k/, we optimized the epitaxial layer structure as well as the conditions of ion implantation into the extrinsic emitter and post-implantation annealing. The best results were obtained when a 5-nm-thick 5/spl times/10/sup 17/-cm/sup -3/-doped GaInP tunnel barrier with a 20-nm-thick undoped GaAs spacer was used at the BC junction, and when 2/spl times/10/sup 12/-cm/sup -2/ 50-keV B implantation was employed followed by 10-min annealing at 390/spl deg/C. Fabricated 40/spl times/40-/spl mu/m/sup 2/ C-up TC-HBTs showed almost zero V/sub CE,sat/ (<10 mV) and a very small V/sub k/ of 0.29 V at a collector current density of 4 kA/cm/sub 2/, which are much lower than those of a typical GaInP/GaAs HBT. The results indicate that the C-up TC-HBT's are attractive candidates for high-efficiency high power amplifiers. 相似文献
8.
Borgarino M. Plana R. Delage S.L. Fantini F. Graffeuil J. 《Electron Devices, IEEE Transactions on》1999,46(1):10-16
In this paper, we report on the early increase of the dc current gain (burn-in effect) due to the electrical stress of carbon doped GaInP/GaAs heterojunction bipolar transistors (HBTs). Devices featuring different passivation layers, base doping, and emitter widths were investigated. The obtained data demonstrate that the burn-in effect is due to a reduction of the surface recombination located at the extrinsic base surface, around the emitter perimeter. It is concluded that the recombination centers are related to defects at the passivation/semiconductor interface and that, during the stress, they are passivated by hydrogen atoms released from C-H complexes 相似文献
9.
《Microelectronics Reliability》1999,39(6-7):1033-1042
The GaAs HBT has recently become the technology of choice in particularly demanding wireless communications applications. However, controversy about HBT reliability is still widespread, with conflicting claims for lifetime and activation energy. Here, we detail the fundamental physics of HBT degradation, and describe the stress factors that drive it. Extensive testing shows that degradation is typically due to the formation of midgap traps associated with crystalline defects in the base. In addition, we describe the physical reasons for the superiority of the GaInP emitter in reliable HBT design. Finally, we show preliminary results of a stress test on large area (2 × 45 μm2) GaInP emitter HBTs which have lasted 5000 hours at 75 kA/cm2, 215 °C with no discernable degradation in device characteristics yet. 相似文献
10.
ZHUCheng ZHANGYong-gang LIAi-zhen 《半导体光子学与技术》2004,10(1):44-47
The AR coatings for GaInP/GaAs tandem solar cell are simulated. Results show that, under the condition of the lack of suitable encapsulation, a very low energy loss could be reached on MgF2/ZnS system;in the case of glass encapsulation,the Al2O3/ZrO2 and Al2O3/TiO2 systems are appropriate choice; for AlInP window layer,the thickness of 30nm is suitable. 相似文献
11.
12.
13.
《Electron Device Letters, IEEE》1985,6(4):175-177
We report the first N-p-n heterojunction bipolar transistor (HBT) using a (Ga,In)P/GaAs heterojunction emitter on a GaAs base. This combination is of interest as a potential alternate to (Al,Ga)As/GaAs, because of theoretical predictions of a larger valence band discontinuity and a smaller conduction band discontinuity, thus eliminating the need for grading of the emitter/base junction. The structure was grown by molecular beam epitaxy, with the base doping (∼1019cm-3) far exceeding the n-type doping ∼517cm-3) of the (Ga,In)P wide gap emitter (Eg = 1.88 eV). Common-emitter current gains of 30 were attained at a current density of 3000 A/cm2, the highest current density achieved without burnout. 相似文献
14.
Analysis of the electrical characteristics of GaInP/GaAs HBTs including the recombination effect 总被引:1,自引:1,他引:0
An analytical model is used to predict the effects of surface recombination current on the gain and transit time of GaInP/GaAs heterojunction bipolar transistors (HBTs). The present analysis shows that consideration of the recombination current gives current gain values that are comparable to those of the experimental results. The dependence of current gain on temperature, base doping and emitter area are also analyzed, and the variation in collector current with emitter-base voltage, temperature and doping is considered. 相似文献
15.
16.
A planar emitter-down AlGaAs/GaAs heterojunction bipolar transistor (HBT) has been fabricated by a molecular beam epitaxy overgrowth of the n-GaAs collector on top of the base layer after the base layer was formed by beryllium implantation and rapid thermal annealing. The emitter down transistors fabricated by this process had DC current gains of 20, and ring oscillators gave a maximum switching speed of 250 ps/gate.<> 相似文献
17.
C. Maneux N. Labat N. Saysset A. Touboul Y. Danto J. Dangla P. Launay J. -M. Dumas 《Microelectronics Reliability》1996,36(11-12)
A field-induced degradation mechanism responsible for the surface base current drift in GaAs HBT's is studied on the basis of accelerated life-tests two stress conditions are applied to HBT's and associated TLM structures. An EDX analysis performed on the base ohmic contact confirms the migration of metallic species which are assessed to spread into the extrinsic base region of AlGaAs/GaAs HBT's. The self-passivated GaInP/GaAs technology is expected to improve the HBT reliability. 相似文献
18.
Yue-Fei Yang Chung-Chi Hsu Hai-Jiang Ou Ta-Chien Huang Yang E.S. 《Electron Devices, IEEE Transactions on》1997,44(12):2122-2127
A C-doped GaInP/GaAs heterojunction bipolar transistor (HBT) with a selective buried sub-collector has been fabricated by two growth steps. The active HBT region was made on the selective buried sub-collector layer with minimum overlap of the extrinsic base and the sub-collector region resulting in substantial reduction of the base-collector capacitance. The experiment shows that the base-collector capacitance is reduced to about half of that of a conventional HBT while the base resistance remains unchanged resulting in a 40-50% increase in the maximum oscillation frequency. Both DC and RF characteristics are investigated and compared with a conventional HBT. A current gain of 40, cutoff frequency of 50 GHz and maximum oscillation frequency of 140 GHz were obtained for the GaInP/GaAs HBT. It is demonstrated that the selective buried sub-collector provides an effective means for enhancing RF performance of an HBT 相似文献
19.
Plana R. van Haaren B. Escotte L. Delage S.L. Blanck H. Graffeuil J. 《Electron Device Letters, IEEE》1997,18(3):108-110
In this paper an annealing procedure which gives an excess noise reduction both of heavily C-doped resistive structures and GaInP/GaAs Heterojunction Bipolar Transistors (HBTs) of 5 dB is proposed. The investigation of the correlation between the noise generators indicate that the annealing leads to a decrease of noise voltage attributed to a strain reduction both in the intrinsic and in the extrinsic base related to a site switching effect of carbon atoms. The reduction of noise current with annealing is attributed to the surface improvement related passivation process by hydrogen atoms 相似文献
20.
Liu W. Fan S. Kim T.S. Beam E.A. III Davito D.B. 《Electron Devices, IEEE Transactions on》1993,40(8):1378-1383
GaInP/GaAs heterojunction bipolar transistors (HBTs) and both graded and abrupt AlGaAs/GaAs HBTs were fabricated. A total of 20 wafers were analyzed. Comparisons of the experimental results establish that the dominant carrier transport mechanism in GaInP/GaAs HBTs is the carrier diffusion through the base layer. This suggests that the conduction-band barrier across the GaInP/GaAs emitter-base junction is so small that the barrier spike does not affect the carrier transport. This result differs from other published results which, by studying device structures other than HBTs, determined the conduction band barrier to be as large as ~50% of the bandgap difference. The findings of the present investigation, however, agree well with another published work which also examined an HBT structure. The difference between these works is discussed 相似文献