共查询到20条相似文献,搜索用时 15 毫秒
1.
We present new, unmistakable experimental evidence directly linking the kink effect with impact ionization in the channel of InAlAs-InGaAs HEMTs on InP. Through the use of a sidegate structure, we confirm that the impact ionization coefficient obeys the classic exponential dependence on the inverse electric field at the drain end of the gate, and that the onset of the kink strongly coincides with the onset of impact ionization in the devices we consider. These measurements illuminate the functional relationship between the kink and impact ionization, and therefore will allow assessment of the numerous impact-ionization related kink mechanisms that have recently been suggested in the literature 相似文献
2.
Wah-Peng Neo Hong Wang Radhakrishnan K. 《Electron Devices, IEEE Transactions on》2003,50(7):1711-1714
Electron impact ionization coefficients (/spl alpha/) in In/sub 0.52/Ga/sub 0.48/P have been extracted based on the measurements of electron multiplication factor in npn InGaP-GaAs-InGaP double heterojunction bipolar transistors (HBTs). The electron ionization coefficient of InGaP determined in this brief extends the previously reported data in low electric field by two orders of magnitude down to 1 cm/sup -1/ with the electric field as low as 330 kV/cm. 相似文献
3.
Zanoni E. Malik R. Pavan P. Nagle J. Paccagnella A. Canali C. 《Electron Device Letters, IEEE》1992,13(5):253-255
Impact ionization phenomena in the collector region of AlGaAs/GaAs heterojunction bipolar transistors give rise to base current reduction and reversal. These phenomena can be characterized by extracting the M -1 coefficient, which can be evaluated by measuring base current changes. Measurements of M -1 are affected at low current densities by the presence of the collector-base junction reverse current I CBO. At high current densities, three effects contribute to lower the measured M -1 value: voltage drops due to collector (R C) and base (R B) parasitic resistances, device self-heating, and lowering of the base-collector junction electric field due to mobile carriers. By appropriately choosing the emitter current value, parasitic phenomena are avoided and the behavior of M -1 as a function of the collector-base voltage V CB in AlGaAs/GaAs HBTs is accurately characterized 相似文献
4.
Umemoto D.K. Velebir J.R. Kobayashi K.W. Oki A.K. Streit D.C. 《Electronics letters》1991,27(17):1517-1518
npn and pnp GaAs/AlGaAs heterojunction bipolar transistors have been successfully fabricated on the same GaAs substrate using selective molecular beam epitaxy and a new merged HBT processing technology. The DC and microwave characteristics of the transistors are equivalent to those of similar HBTs grown by conventional MBE on separate GaAs substrates.<> 相似文献
5.
J. H. Tsai W. Ch. Liu D. F. Guo Y. Ch. Kang Sh. Y. Chiu W. Sh. Lour 《Semiconductors》2008,42(3):346-349
The dc performances of an InP/InGaAs pnp heterostructure-emitter bipolar transistor are investigated by theoretical analysis and experimental results. Though the
valence band discontinuity at the InP/InGaAs heterojunction is relatively large, the addition of a heavily-doped as well as
thin p
+-InGaAs emitter layer between p-InP confinement and n
+-InGaAs base layers effectively eliminates the potential spike at emitter-base junction and simultaneously lowers the emitter-collector
offset voltage and increases the potential barrier for electrons. Experimentally, a high current gain of 88 and a low offset
voltage of 54 mV have been achieved.
The text was submitted by the authors in English. 相似文献
6.
Datta S. Shen Shi Roenker K.P. Cahay M.M. Stanchina W.E. 《Electron Devices, IEEE Transactions on》1998,45(8):1634-1643
The performance capabilities of InP-based pnp heterojunction bipolar transistors (HBT's) have been investigated using a drift-diffusion transport model based on a commercial numerical simulator. The low hole mobility in the base is found to limit the current gain and the base transit time, which limits the device's cutoff frequency. The high electron majority carrier mobility in the n+ InGaAs base allows a reduction in the base doping and width while maintaining an adequately low base resistance. As a result, high current gain (>300) and power gain (>40 dB) are found to be possible at microwave frequencies. A cutoff frequency as high as 23 GHz and a maximum frequency of oscillation as high as 34 GHz are found to be possible without base grading. Comparison is made with the available, reported experimental results and good agreement is found. The analysis indicates that high-performance pnp InP-based HBT's are feasible, but that optimization of the transistor's multilayer structure is different than for the npn device 相似文献
7.
Measurements and Monte Carlo simulations of impact ionization in the base-collector region of SiGe HBTs are presented. A device with low germanium concentration (graded from 0 to 12%) is considered and no differences are found between the experimental multiplication factor in that device and the corresponding silicon control. Because impact ionization (II) occurs inside the bulk-Si collector, phonon and II scattering rates for bulk silicon can be used in the Monte Carlo simulation, avoiding the need to model the strained SiGe layers. Full-Band Monte Carlo simulations are shown to reproduce the multiplication factors measured in SiGe devices featuring different collector profiles 相似文献
8.
Slater D.B. Jr. Enquist P.M. Najjar F.E. Chen M.Y. Hutchby J.A. Morris A.S. Trew R.J. 《Electron Device Letters, IEEE》1991,12(2):54-56
The diffusion coefficient (D h) and a value for the collector velocity (v h) of holes in AlGaAs/GaAs P-n-p HBTs (heterojunction bipolar transistors) were obtained from high-frequency measurements on structures with different base and collector widths. Quantities for D h and v h of 5.6 cm2/s and 5.5×106 cm/s, respectively, were obtained by plotting the total emitter-collector delay versus inverse emitter current and extrapolating the data to infinite emitter current to obtain the base and collector transit delays. An f t and f max as high as 15 and 29 GHz, respectively, were obtained for non-self-aligned (1-μm emitter mesa/base contact separation) devices with a 2.6-μm×10-μm emitter 相似文献
9.
The low-frequency noise characteristics of p-n-p InAlAs/InGaAs heterojunction bipolar transistors (HBTs) were investigated. Devices with various geometries were measured under different bias conditions. The base noise current spectral density (3.11 /spl times/ 10/sup -16/ A/sup 2//Hz) was found to be higher than the collector noise current spectral density (1.48 /spl times/ 10/sup -16/ A/sup 2//Hz) at 10 Hz under low bias condition (I/sub C/=1 mA, V/sub EC/=1 V), while the base noise current spectral density (2.04 /spl times/ 10/sup -15/ A/sup 2//Hz) is lower than the collector noise current spectral density (7.87 /spl times/ 10/sup -15/ A/sup 2//Hz) under high bias condition (I/sub C/=10 mA, V/sub EC/=2 V). The low-frequency noise sources were identified using the emitter-feedback technique. The results suggest that the low-frequency noise is a surface-related process. In addition, the dominant noise sources varied with bias levels. 相似文献
10.
Daumann W. Ellrodt P. Brockerhoff W. Bertenburg R. Reuter R. Auer U. Molls W. Tegude F.-J. 《Electron Device Letters, IEEE》1996,17(10):488-490
InAlAs/InGaAs dual-gate-HFETs (DGHFETs) and single-gate-HFETs (SGHFETs) have been fabricated and characterized with special emphasis on reducing the impact ionization. For the first time it is shown that in the case of the DGHFET, due to the second gate (VG2S=0 V), impact ionization can be totally prevented in the channel underneath the RF-driven gate without reduction of the RF-relevant parameters such as transconductance, output resistance and voltage gain. The electric field and the potential distribution in the channel are discussed using a nomogram and confirmed by 2-D simulation. According to VG2S=0 V, a new cascode design is presented by directly connecting the second gate to the source (ground) 相似文献
11.
Surface-recombination-free InGaAs/InP HBTs with graded base have been demonstrated. The HBTs were passivated by ammonium sulfide. The current gain of the nonself-aligned HBTs was independent of the emitter periphery, indicating that the surface recombination was removed by the passivation. For the self-aligned HBTs, the current gain was still dependent on the emitter periphery after the passivation due to the base contact recombination. A surface leakage channel has been identified to result in a significant increase in the base contact recombination. The passivation has two effects: one is the surface recombination velocity reduction and the other is the surface leakage channel elimination. 相似文献
12.
The base-collector capacitance Cbc and the collector transit time delay τc govern the high-speed performance of modern heterojunction bipolar transistors (HBTs). Both are shown to be strongly modified by velocity modulation effects in InP/InGaAs HBTs: The carrier velocity in the collector depends on Vcb and Ic, causing a reduction of Cbc and τc respectively. The current induced transit time modulation is shown to be conveniently expressed by a minor but important modification of the conventional transit time delay expression. Particle simulations are performed to assess the relevance of these effects 相似文献
13.
Jae-Chun Han Jong-In Song Sung-Woong Park Deokha Woo 《Electron Devices, IEEE Transactions on》2002,49(1):1-6
Growth of ultrahigh carbon-doped p-type InGaAs lattice matched to InP by chemical beam epitaxy (CBE) using carbon tetrabromide (CBr4 ) as a doping source was investigated. Effects of growth temperature, group V supply pressure, and CBr4 supply pressure on growth rate, composition, mobility, and hole concentration of carbon-doped InGaAs were studied. Ultrahigh net hole concentration and room-temperature mobility of 2 × 1020/cm3 and 33 cm2/V·sec, respectively, were achieved. Mobility of the ultrahigh carbon-doped InGaAs using CBr4 compared favorably to those of CBE grown carbon-doped InGaAs using carbon tetrachloride (CCl4) and molecular beam epitaxy grown beryllium (Be)-doped InGaAs grown at low temperature. The highly carbon-doped InGaAs layers grown by CBE using CBr4 as a doping source showed a negligible hydrogen passivation effect and were used for the growth of high-performance, highly carbon-doped base InP/InGaAs heterojunction bipolar transistor epitaxial layer structures 相似文献
14.
Mathew T. Kim H.-J. Scott D. Jaganathan S. Krishnan S. Wei Y. Urteaga M. Long S. Rodwell M.J.W. 《Electronics letters》2001,37(11):667-668
A 75 GHz static frequency divider in InAlAs/InGaAs transferred-substrate heterojunction bipolar transistor (HBT) technology is reported. This is the highest reported frequency of operation for a static frequency divider. The circuit has 60 transistors and dissipates 800 mW. The divider was operated at a clock frequency of 5.0 to 75 GHz 相似文献
15.
Hong Wang Geok Ing Ng 《Electron Devices, IEEE Transactions on》2001,48(11):2647-2654
In this paper, we report on the degradation of DC performance of InP/InGaAs/InP double heterojunction bipolar transistors (DHBTs) during electrical stress. Devices with different sizes were investigated under highly reverse base-collector (B-C) bias stress. The increase of B-C and emitter-base (E-B) junction leakage and decrease of current gain were observed. The increase of the junction leakage for both B-C and E-B junctions was found to scale with the junction perimeters which suggests that the stress-induced damages are localized at the junction peripheries. For the devices with larger emitter periphery-to-area ratio, a more pronounced decrease of current gain due to the stress was observed. The obtained experimental data indicate that the stress-induced degradation happens in high reverse B-C bias voltage (avalanche) regime. The degradation is believed to be induced by hot carriers rather than current. A physical model is proposed to explain the experimental observations 相似文献
16.
Impact ionization in InAlAs/InGaAs HFET's 总被引:1,自引:0,他引:1
The presence of an energy barrier to the transfer of holes from the channel to the gate electrode of InAlAs/InGaAs HFET's prevents the gate current from being a reliable indicator of impact ionization. Consequently, we have used a specially designed sidegate structure to demonstrate that due to the narrow bandgap of InGaAs, impact ionization takes place in the channel of these devices under normal operating conditions. The ionization coefficient was found to follow a classic exponential dependence on the inverse electric field at the drain end of the gate, for over three orders of magnitude 相似文献
17.
18.
The kink effect and excess gate current in InAlAs/InGaAs/InAlAs HEMT's have been linked to impact ionization in the high field region of the channel. In this letter, a relationship is established between experimentally measured excess gate current and the tunneling of holes from the quantum well formed in the channel. The channel hole current is then obtained as the quotient of the excess gate current to the gate-voltage-dependent transmission probability. This channel hole current follows the exponential dependence of the ionization constant on the inverse electric field 相似文献
19.
Suzuki Y. Shimawaki H. Amamiya Y. Nagano N. Yano H. Honjo K. 《Solid-State Circuits, IEEE Journal of》1999,34(2):143-147
A preamplifier for 40-Gb/s optical transmission systems incorporating AlGaAs/InGaAs heterojunction bipolar transistors (HBTs) with p+ regrown extrinsic base layers is described. The HBTs have a heavily doped regrown p+-GaAs layer in the extrinsic base regions and a thin graded InGaAs strained layer for the intrinsic base. Their measured peak fmax is above 200 GHz. The developed preamplifier provides a bandwidth of 38.4 GHz and a transimpedance gain of 41.1 dB Ω. Moreover, the frequency response as an optical receiver has a bandwidth of 32 GHz. These characteristics make the preamplifier suitable for use in a 40-Gb/s optical receiver. These results show that AlGaAs/InGaAs HBTs with p+ regrown extrinsic base layers are very promising for use in 40-Gb/s optical transmission systems 相似文献
20.
The effects of impact ionization in the InGaAs absorption layer on the multiplication, excess noise and breakdown voltage are modeled for avalanche photodiodes (APDs), both with InP and with InAlAs multiplication regions. The calculations allow for dead space effects and for the low field electron ionization observed in InGaAs. The results confirm that impact ionization in the InGaAs absorption layer increases the excess noise in InP APDs and that the effect imposes tight constraints on the doping of the charge control layer if avalanche noise is to be minimized. However, the excess noise of InAlAs APDs is predicted to be reduced by impact ionization in the InGaAs layer. Furthermore the breakdown voltage of InAlAs APDs is less sensitive to ionization in the InGaAs layer and these results increase tolerance to doping variations in the field control layer. 相似文献