InAs/AlSb/GaSb resonant interband tunneling diodes and Au-on-InAs/AlSb-superlattice Schottky diodes for logic circuits

Chow, D. H.; Dunlap, H. L.; Williamson, W. S.; Enquist, S.B.; Gilbert, Barry K.; Subramaniam, S.; Lei, Peiming; Bernstein, Gary H.

doi:10.1109/55.484126

Cited by 55 publications

(27 citation statements)

References 11 publications

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“…22 Such measurements could be used as a routine characterization tool for antimonide MBE or metalorganic chemical vapor deposition systems, similar to GaAs͑Si͒ epilayers for arsenide systems. Other materials such as GaSb and InSb would be less suitable because undoped GaSb epilayers are p-type, 23 with (N A ϪN D )Ͼ10 16 /cm 3 , and InSb has a high intrinsic carrier concentration, n i ϳ2ϫ10 16 /cm 3 at 300 K.…”

Section: Discussionmentioning

confidence: 99%

“…For example, AlSb can serve as a barrier material to confine electrons in InAs-channel high electron mobility transistors 1 or magnetoelectronic hybrid Hall effect devices. 2 AlSb layers also can function as tunneling barriers in resonant tunneling diodes 3 and as barriers in ''W'' infrared lasers with InAs/InGaSb/InAs active regions. 4 A few studies of the optical 5,6 and structural 7 properties of epitaxial AlSb have been reported.…”

Section: Introductionmentioning

confidence: 99%

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Transport properties of Be- and Si-doped AlSb

Bennett

Moore

Yang

et al. 2000

Journal of Applied Physics

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Thick epitaxial layers of AlSb͑Si͒ and AlSb͑Be͒ were grown by molecular beam epitaxy and characterized by variable-temperature Hall/van der Pauw measurements. Si is shown to be predominantly an acceptor in AlSb, with an energy level 33Ϯ4 meV above the top of the valence band. Be is also an acceptor, with an energy level 38Ϯ4 meV above the top of the valence band. Be is a robust doping source for p-AlSb for carrier densities ranging from 10 15 to 10 19 cm Ϫ3 . Background impurity levels in AlSb can be assessed by measuring the transport properties of lightly doped AlSb͑Be͒ layers.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transport properties of Be- and Si-doped AlSb

Bennett

Moore

Yang

et al. 2000

Journal of Applied Physics

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“…[3][4][5] For the above applications the peak current density ͑PCD͒ and the current peak-to-valley ratio ͑PVR͒ are the two major figures of merit. 2,6 Also, the choice of material system is of great importance.…”

Section: ͓S0003-6951͑97͒02821-0͔mentioning

confidence: 99%

High peak-current-density strained-layer In0.3Ga0.7As/Al0.8Ga0.2As resonant tunneling diodes grown by metal-organic chemical vapor deposition

Mirabedini

Mawst

Botez

et al. 1997

Applied Physics Letters

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Peak current densities two times higher than the best values reported for GaAs-based resonant tunneling diode ͑RTD͒ structures have been obtained from metal-organic chemical-vapor deposition ͑MOCVD͒-grown deep-quantum-well strained-layer In 0.3 Ga 0.7 As/Al 0.8 Ga 0.2 As RTDs. By growing on nominally exact ͑100͒ ϩ/Ϫ0.1°GaAs substrates, we have been able to obtain smooth interfaces between the strained-layer In 0.3 Ga 0.7 As quantum well and Al 0.8 Ga 0.2 As barriers, which, in turn, enabled us to benefit from resonant tunneling through the second resonant energy level of In 0.3 Ga 0.7 As/Al 0.8 Ga 0.2 As structures. Peak current densities in excess of 300 kA/cm 2 , and peak-to-valley current ratios as high as 3:1, at 300 K, have been obtained from structures with 14-Å-thick barriers and a 57-Å-thick well. © 1997 American Institute of Physics. ͓S0003-6951͑97͒02821-0͔Currently, resonant tunneling diodes ͑RTDs͒ are the widest bandwidth semiconductor devices with gain, which have been used to build microwave oscillators with oscillation frequencies in excess of 700 GHz, 1 trigger circuits operating up to 110 GHz, 2 and a wide range of high-speed logic and switching circuits. 3-5 For the above applications the peak current density ͑PCD͒ and the current peak-to-valley ratio ͑PVR͒ are the two major figures of merit. 2,6 Also, the choice of material system is of great importance. GaAsbased RTDs are favored over GaSb-and InP-based structures for practical applications due to the maturity of growth and material processing techniques as well as the possibility of integration with other high-speed devices. 7 The best reported PCD value for GaAs-based RTDs 8 is 140 kA/cm 2 , achieved from a Schottky-collector AlAs/GaAs structure having a PVR of 2:1. As for RTDs grown by the metal-organicchemical-vapor deposition ͑MOCVD͒ technique, the PCD values reported 9 are at best 96 kA/cm 2 . Here we report on MOCVD-grown GaAs-based RTDs operating at room temperature with PCDs in excess of 300 kA/cm 2 and PVRs as high as 3:1, made possible by resonant tunneling through the second energy level of a deep quantum well in a strainedlayer structure with smooth quantum-well interfaces.The initial measurements done by Broekaert et al., 10 show that, in an In 0.53 Ga 0.47 As/AlAs/InAs structure grown on InP substrate, the PCD for the resonant tunneling through the second energy level is almost ten times greater than the PCD associated with the first energy level for the same structure. However, the peak voltage for the second resonant energy level is so high (ϳ4.1 V) that it makes the use of tunneling through the second level highly impractical for any application. A later report by Mehdi et al. 6 shows that by using a deep quantum well and adjusting the second resonant energy level to the bottom of conduction band, it is possible to obtain higher PCD values at low peak voltages compared to the conventionally designed RTDs. However, PVRs measured for such structures did not exceed 2:1 at room temperature. Reports on GaAs-based strained-layer I...

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“…These semiconductors can have a high electron mobility 1 and offer a wide range of electronic band gaps, band offsets, and electronic barriers. 2 Although several notable device [3][4][5] and circuit 6,7 demonstrations have been made using these materials, the absence of lattice matched, insulating substrates remains an issue, particularly for minority carrier devices. Bulk-grown GaSb is the most widely available substrate for the near lattice-matched epitaxial growth of these materials.…”

mentioning

confidence: 99%

Fabrication of InAs/AlSb/GaSb heterojunction bipolar transistors on Al2O3 substrates by wafer bonding

Moran

Chow

Hunter

et al. 2001

Applied Physics Letters

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High-frequency integrated circuit applications of GaSb-based materials are hampered by the lack of a suitable lattice-matched insulating substrate. Wafer bonding was used to fabricate InAs/AlSb/ GaSb-based heterojunction bipolar transistors ͑HBTs͒ on an insulating sapphire substrate through a low temperature bonding process that results in a high bond strength and permitted the mechanical and chemomechanical removal of the initial GaSb substrate. The use of selective etches allows for the retention of the epitaxial device layers over virtually the entire wafer area. Minimal degradation of the transferred layers occurred in the bonding and substrate removal process. The resulting transferred structures were fabricated into functional HBTs exhibiting a dc current gain of ϳ5. Significant interest is presently focused on the development of electronic devices based on InAs, GaSb, AlSb, and their alloys with lattice constants near 0.61 nm. These semiconductors can have a high electron mobility 1 and offer a wide range of electronic band gaps, band offsets, and electronic barriers. 2 Although several notable device 3-5 and circuit 6,7 demonstrations have been made using these materials, the absence of lattice matched, insulating substrates remains an issue, particularly for minority carrier devices. Bulk-grown GaSb is the most widely available substrate for the near lattice-matched epitaxial growth of these materials. GaSb is not, however, available in semi-insulating form. A semi-insulating substrate or insulating platform is critical for many applications due to high parasitic capacitances which arise when metal interconnect lines are placed above conductive substrate materials. Sapphire substrates have the dielectric properties suitable for such applications, 8 but are not suitable for direct heteroepitaxial growth due to the large lattice and thermal expansion coefficient mismatch.To realize InAs/AlSb/GaSb heterostructure devices on insulating substrates, we have grown epitaxial layers on lattice-matched GaSb substrates and directly bonded the layers to a suitable insulating platform, i.e., Al 2 O 3 . The initial GaSb substrate is removed and the remaining layers are processed into device structures. The wafer bond between the Al 2 O 3 and the epitaxial surface layer is demonstrated to be strong enough to withstand the subsequent processing associated with GaSb substrate removal. In this process, the ϳ500 m GaSb substrate is completely removed, leaving the Ͻ1 m thick device layer intact. Highly selective etching is used to fabricate a device from the transferred layers. Additionally, any structural degradation or changes in strain of the layers due to the bond-and-transfer processes is assessed.The characterization of devices fabricated from the transferred layers is used to determine the device-level impact of the bond-and-transfer processing.Heterojunction bipolar transistor ͑HBT͒ structures were grown by molecular beam epitaxy ͑MBE͒ on ͑100͒-oriented GaSb substrates at a substrate temperature of 480°C. An invert...

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InAs/AlSb/GaSb resonant interband tunneling diodes and Au-on-InAs/AlSb-superlattice Schottky diodes for logic circuits

Cited by 55 publications

References 11 publications

Transport properties of Be- and Si-doped AlSb

Transport properties of Be- and Si-doped AlSb

High peak-current-density strained-layer In0.3Ga0.7As/Al0.8Ga0.2As resonant tunneling diodes grown by metal-organic chemical vapor deposition

Fabrication of InAs/AlSb/GaSb heterojunction bipolar transistors on Al2O3 substrates by wafer bonding

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