The physics of the growth mechanisms, characterization of epitaxial structures and device properties of GaAs and other compound semiconductors on Si are reviewed in this paper. The nontrivial problems associated with the heteroepitaxial growth schemes and methods that are generally applied in the growth of lattice mismatched and polar on nonpolar material systems are described in detail. The properties of devices fabricated in GaAs and other compound semiconductors grown on Si substrates are discussed in comparison with those grown on GaAs substrates. The advantages of GaAs and other compound semiconductors on Si, namely, the low cost, superior mechanical strength, and thermal conductivity, increased wafer area, and the possibility of monolithic integration of electronic and optical devices are also discussed.

Gallium arsenide and other compound semiconductors on silicon

The collector-emitter offset voltages of InAlAs/InGaAs heterojunction bipolar transistors grown by molecular-beam epitaxy are discussed. Both the difference between emitter and collector areas and electrical asymmetry between emitter and collector junctions in these mesa-isolated transistors account for the offset voltages observed. Devices exhibited offset voltages in the range of 50-300 mV, depending on the structures and device sizes. Several electrical and geometrical factors affecting the offset voltage are discussed in detail. >

Collector offset voltage of heterojunction bipolar transistors grown by molecular beam epitaxy

X‐ray photoemission spectroscopy (XPS) has been used to measure the valence‐band offset ΔEv for the lattice‐matched InP/ In0.53Ga0.47As and In0.53Ga0.47As/ In0.52Al0.48As heterojunction interfaces. The heterojunctions were formed by molecular‐beam epitaxy. We obtain values of ΔEv (InP/In0.53Ga0.47As) =0.34 eV (ΔEc/ ΔEv=43/57) and ΔEv (In0.53Ga0.47As/ In0.52Al0.48As) =0.22 eV (ΔEc/ ΔEv =68/32) for the respective interfaces. By combining these measurements with available XPS ΔEv (InP/ In0.52Al0.48As) data we find that band offset transitivity is satisfied. Accordingly, the band offsets for heterojunction pairs formed from InP, In0.53Ga0.47As, and In0.52Al0.48As are not influenced by interface specific effects.

Measurement of InP/In0.53Ga0.47As and In0.53Ga0.47As/In0.52Al0.48As heterojunction band offsets by x‐ray photoemission spectroscopy

A theoretical investigation of Si/Si/sub 1-x/Ge/sub x/ heterojunction bipolar transistors (HBTs) undertaken in an attempt to determine their speed potential is discussed. The analysis is based on a compact transistor model, and devices with self-aligned geometry, including both extrinsic and intrinsic parameters, are considered. For an emitter area of 1*5 mu m/sup 2/, an f/sub t/ of over 75 GHz and f/sub max/ of over 35 GHz were computed at a collector current density of 1*10/sup 5/ A/cm/sup 2/ and V/sub CB/ of 5 V. >

High-speed performance of Si/Si/sub 1-x/Ge/sub x/ heterojunction bipolar transistors

Epitaxial lift-off (ELO) technique was used for the first time to transplant AlGaAs/GaAs Heterojunction Bipolar Transistors (HBT's) to Si substrates. Both preprocessed (devices processed before transplantation) and postprocessed (devices processed after transplantation) ELO HBT's on Si were demonstrated in this study. The characteristics of those HBT's on Si with either technique show nearly identical characteristics of the HBT's on GaAs without transplantation, indicating the film quality is maintained after transplantation. Devices with a high current gain of 550 were transplanted without any degradation, and the current gain is not limited by the ELO process. This current gain value is the highest reported for GaAs HBT's on Si with any techniques. >

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AlGaAs/GaAs Heterojunction Bipolar Transistors on Si substrate using epitaxial lift-off

High-gain GaAs/AlGaAs n-p-n heterojunction bipolar transistors (HBT's) on Si substrates grown by molecular beam epitaxy (MBE) have been fabricated and tested. In this structure, an n/sup +/-InAs emitter cap layer was grown in order to achieve a nonalloyed ohmic contact. Typical devices with an emitter dimension of 50*50 mu m/sup 2/ exhibited a current gain as high as 45 at a collector current density of 2*10/sup 3/ A/cm/sup 2/ with an ideality factor of 1.4. This is the highest current gain reported for HBT's grown on Si substrates. Breakdown voltages as high as 10 and 15 V were observed for the emitter-base and collector-base junctions respectively. The investigation on devices with varying emitter dimensions demonstrates that much higher current gains can be expected. >

A high-gain GaAs/AlGaAs n-p-n heterojunction bipolar transistor on

An InGaAs/InAlAs double-heterojunction bipolar transistor (DHBT) on InP(n) grown by molecular-beam epitaxy (MBE) that exhibits high DC performance is discussed. An n/sup +/-InAs emitter cap layer was used for nonalloyed contacts in the structure and specific contact resistances of 1.8*10/sup -7/ and 6.0*10/sup -6/ Omega -cm/sup 2/ were measured for the nonalloyed emitter and base contacts, respectively. Since no high-temperature annealing is necessary, excellent contact surface morphology on thinner base devices can easily be obtained. In devices with 50*50- mu m/sup 2/ emitter area, common-emitter current gains as high as 1500 were achieved at a collector current density of 2.7*10/sup 3/ A/cm/sup 2/. The current gain increased up to 2000 for alloyed devices. >

A high-performance InGaAs/InAlAs double-heterojunction bipolar transistor with nonalloyed n/sup +/-InAs cap layer on InP(n) grown by molecular beam epitaxy

GaAs/AlGaAs Pnp heterojunction bipolar transistors (HBTs) were fabricated and tested on (100) Si substrates for the first time A common-emitter current gain of β=8 was measured for the typical devices with an emitter area of 50×50 μm^2 at a collector current density of 1×10^(4) A/cm^2 with no output negative differential resistance up to 280 mA, highest current used A very high base-collector breakdown voltage of 10 V was obtained Comparing the similar structures grown on GaAs substrates, the measured characteristics clearly demonstrate that device grade hole injection can be obtained in GaAs on Si epitaxial layers despite the presence of dislocations

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GaAs/AlGaAs heterojunction Pnp bipolar transistors grown on (100) Si by molecular beam epitaxy

The vertical and lateral diffusion of the contact metal during thermal processing become increasingly critical as device dimensions shrink. To alleviate these problems while achieving low contact resistances, InAs contact layers have been used to facilitate the formation of nonalloyed ohmic contacts in n-p-n and p-n-p double-heterojunction bipolar transistors (DHBTs) grown by MBE on

T. Won

Papers

A high-gain GaAs/AlGaAs n-p-n heterojunction bipolar transistor on

A high-performance InGaAs/InAlAs double-heterojunction bipolar transistor with nonalloyed n/sup +/-InAs cap layer on InP(n) grown by molecular beam epitaxy

GaAs/AlGaAs heterojunction Pnp bipolar transistors grown on (100) Si by molecular beam epitaxy

High-gain n-p-n and p-n-p InGaAs/InAlAs double-heterojunction bipolar transistors with InAs cap layers by molecular-beam epitaxy