S. B. Hyder

Saturation velocity determination for In0.53Ga0.47As field‐effect transistors

The fabrication of Schottky‐gate field‐effect transistors (FET’s) on InGaAs lattice matched to InP is reported. A higher band‐gap interface layer is used to lower the gate leakage to acceptable levels. A technique to deduce the effective saturated electron drift velocity is given, which shows over a factor of 2 higher saturated velocity for InGaAs in comparison to GaAs when used as a FET material.

Vapor‐phase epitaxial growth of InGaAs lattice matched to (100) InP for photodiode application

Vapor‐phase epitaxial growth of In0.53Ga0.47As lattice matched to (100) ‐oriented InP substrates is described, and the performance of photodiodes fabricated from this material is presented. Gas‐flow conditions for lattice‐matched growth with various Ga‐CHl flows were established for growth using the hydride process. The effect of substrate temperature on gas‐flow ratios necessary for lattice‐matched growth was studied over the temperature range 650–750 °C. Growth rates were found to vary from about 8 to about 60 μm/h over this temperature range. The activation energy of surface reaction was determined to be 44 kcal/mole. Photodiodes fabricated from an InP/In0.53Ga0.47As/InP structure showed rise and fall times of ≲1 nsec with quantum efficiencies in excess of 95% at 1.22 μm.

Field‐assisted photoemission to 2.1 microns from a Ag/p‐In0.77Ga0.23As photocathode

Reflection‐mode photoemission to a 2.1‐μm threshold has been achieved from an externally biased Ag/p‐In0.77Ga0.23As cathode. Quantum yield at 1.9 μm is 2×10−3 electrons per incident photon for 2.4‐V bias and a cathode cooled to ∼125 K. The cathode was grown by vapor‐phase epitaxy on a compositionally graded InAsP on InP (100) substrate using the hydride process.

Liquid‐phase‐epitaxial growth of lattice‐matched In0.53Ga0.47As on (100) ‐oriented InP

Growth of InGaAs lattice matched to InP was achieved for the first time on the (100) orientation of InP by liquid‐phase epitaxy. Growth conditions and melt composition for such a growth are presented. In0.53Ga0.47As/InP and InP/In0.53Ga0.47As/InP heterojunction structures for 1.7‐μm field‐assisted photocathodes have also been fabricated on (100) InP substrates.

Vapor phase epitaxial growth of InP-based compound semiconductor materials

Abstract This paper reviews and extends the work done at Varians Solid State Research Laboratory on the epitaxial growth of In x Ga 1- x As y P 1- y alloys on InP substrates. Growth of In 0.53 Ga 0.47 As with 0.75 eV bandgap whem lattice matched to InP is also described. Gas flow ratios for lattice-matched growths are presented and effect of source and substrate temperature on other growth parameters is discussed. Material characterization was done by optical microscopy, X-ray diffraction, photoluminescence and van der Pauw analysis. Electrical data indicated lower-than-InP mobility for quaternary material. Lattice-matched In 0.53 Ga 0.47 As on InP showed average background doping of about 4 x 10 15 cm -3 with best background of 8 x 10 14 cm -3 . Best room temperature mobility of InGaAs was 5826 cm 2 /V·s for a doping of 8 x 10 15 cm -3 and best 77 K mobility was 20,200 cm 2 /V·s.

Transferred‐electron photoemission to 1.65 μm from InGaAs

Photoemission to 1.65 μm has been achieved in the reflection mode from a bias‐assisted p‐InGaAs cathode. Quantum yield at 1.55 μm is ∼10−3 at 125 K and ∼10−4 at 300 K.

Quantum efficiency of InP field‐assisted photocathodes

Reflection‐mode quantum efficiencies have been calculated for the p‐InP bias‐assisted photoemitter (TE cathode) and have been found to be consistent with experimental data. The calculations, using Monte Carlo techniques, consider the transport of photogenerated electrons to the surface as well as the transmission of electrons at the surface into vacuum. Dependence of the predicted yield upon bias voltage and doping is discussed. Acceptor doping in the mid 1016/cm3 range is indicated as a good choice for a high quantum efficiency photocathode.

Field-assisted semiconductor photoemitters for the 1—2-µm range

Photoemission data and model calculations are presented for a field-assisted semiconductor photoemitter which has achieved reflection-mode quantum efficiencies as high as 8.0 percent at 1.55 µm. The cathodes are p-p heterostructures employing lattice-matched InP-InGaAsP alloys. A thin electron semitransparent Schottky barrier provides the biasing contact for field-assisted electron emission. Parameters for optimal photoemission and sources of dark-current emission are discussed.

Vapor‐phase epitaxial growth of quaternary In1−xGaxAsyP1−y in the 0.75–1.35‐eV band‐gap range

Growth of In1−xGaxAsyP1−y quaternaries on InP (100) substrates was obtained over the whole band‐gap range 0.75–1.35 eV. Growth conditions and gas flow ratios are described for an open tube VPE of these quaternaries.

The incorporation of Ga during LPE growth of In0.53Ga0.47As on (111)B and (100) InP substrates

We report the temperature dependence of the incorporation of Ga during LPE growth of In0.53Ga0.47As on (111) B‐ and (100) ‐oriented InP substrates. The distribution coefficients of Ga can be accurately represented by KGa(111)B =6.40×10−6 exp(1.10/kT) and KGa(100)=5.02×10−13 exp(2.37/kT), which are equal at 629 °C. The difference in activation energies is the source of the ’’discrepancy’’ reported by Pearsall etal. that KGa(111)B<KGa(100) at 621 °C while from our results KGa(111)B≳KGa(100) at 650 °C.