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Showing papers by "Stephen J. Pearton published in 1992"


Journal ArticleDOI
TL;DR: In this paper, a new microlaser design based on the highreflectivity whisperinggallery modes around the edge of a thin semiconductor microdisk is described and initial experimental results are presented.
Abstract: A new microlaser design based on the high‐reflectivity whispering‐gallery modes around the edge of a thin semiconductor microdisk is described and initial experimental results are presented. Optical confinement within the thin disk plane results in a microresonator with potential for single‐mode, ultralow threshold lasers. Initial experiments use selective etching techniques in the InP/InGaAsP system to achieve 3–10 μm diameter disks as thin as 500 A suspended in air or SiO2 on an InP pedestal. Optically pumped InGaAs quantum wells provide sufficient gain when cooled with liquid nitrogen to obtain single‐mode lasing at 1.3 and 1.5 μm wavelengths with threshold pump powers below 100 μW.

1,383 citations


Book
01 Jan 1992
TL;DR: A review of the properties of hydrogen in crystalline semiconductors is presented in this paper, together with the reactions of atomic hydrogen with shallow and deep level impurities that passivate their electrical activity.
Abstract: A review of the properties of hydrogen in crystalline semiconductors is presented. The equilibrium lattice positions of the various states of hydrogen are detailed, together with the reactions of atomic hydrogen with shallow and deep level impurities that passivate their electrical activity. Evidence for several charge states of mobile hydrogen provides a consistent picture for both the temperature dependence of its diffusivity and the chemical reactions with shallow level dopants. The electrical and optical characteristics of hydrogen-related defects in both elemental and compound semiconductors are discussed, along with the surface damage caused by hydrogen bombardment. The bonding configurations of hydrogen on semiconductor surfaces and the prevalence of its incorporation during many benign processing steps are reviewed. We conclude by identifying the most important areas for future effort.

530 citations


Journal ArticleDOI
TL;DR: In this article, a review of hydrogen interactions with imperfections in crystalline metals and semiconductors is presented, focusing on mechanistic experiments and theoretical advances contributing to predictive understanding.
Abstract: Hydrogen interactions with imperfections in crystalline metals and semiconductors are reviewed. Emphasis is given to mechanistic experiments and theoretical advances contributing to predictive understanding. Important directions for future research are discussed.

427 citations


Journal ArticleDOI
TL;DR: The capacitance signal resulting from single electrons tunneling into discrete quantum levels is observed and the nature of the bound states is deduced from the magnetic field evolution of the spectrum.
Abstract: We observe the capacitance signal resulting from single electrons tunneling into discrete quantum levels. The electrons tunnel between a metallic layer and confined states of a single disk in a microscopic capacitor fabricated in GaAs. Charge transfer occurs only for bias voltages at which a quantum level resonates with the Fermi energy of the metallic layer. This creates a sequence of distinct capacitance peaks whose bias positions directly reflect the electronic spectrum of the confined structure. From the magnetic field evolution of the spectrum, we deduce the nature of the bound states.

378 citations


Journal ArticleDOI
TL;DR: In this article, a whispering-gallery mode microdisc laser with singlemode operation and submilliamp threshold current at room temperature was demonstrated, and it was shown that the single-mode operation can achieve sub-milliamps threshold current.
Abstract: Electrically pumped whispering-gallery mode microdisc lasers with singlemode operation and submilliamp threshold current at room temperature are demonstrated.

144 citations


Journal ArticleDOI
TL;DR: In this article, the etch rate of InGaP in a 1:1:1 mixture is thermally activated of the formR ∝.............. �� ��e^{ - E_a /kT} $$======, whereE.............. a = 11.25 kCal · mole−1.
Abstract: Dry and wet chemical etching of epitaxial In0, 5Ga0.5P layers grown on GaAs substrates by gas-source molecular beam epitaxy have been investigated. For chlorine-based dry etch mixtures (PCl3/Ar or CC12F2/Ar) the etching rate of InGaP increases linearly with dc self-bias on the sample, whereas CH4/H2-based mixtures produce slower etch rates. Selectivities of ≥500 for etching GaAs over InGaP are obtained under low bias conditions with PCl3/Ar, but the surface morphologies of InGaP are rough. Both CC12F2/Ar and CH4/H2/Ar mixtures produce smooth surface morphologies and good (≥10) selectivities for etching GaAs over InGaP. The wet chemical etching rates of InGaP in H3PO4:HC1:H2O mixtures has been systemically measured as a function of etch formulation and are most rapid (∼1 μn · min−1) for high HCl compositions. The etch rate,R, in a 1:1:1 mixture is thermally activated of the formR ∝ $$e^{ - E_a /kT} $$ , whereE a = 11.25 kCal · mole−1. This is consistent with the etching being reaction-limited at the surface. This etch mixture is selective for InGaP over GaAs.

85 citations


Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate for the first time that carbon-doped GaAs/AlGaAs heterojunction bipolar transistors (HBTs) can be overcome through the use of InGaP.
Abstract: Carbon‐doped GaAs/AlGaAs heterojunction bipolar transistors (HBTs) typically exhibit severe leakage at the base‐emitter interface which limits their utility for low‐current applications. Furthermore, the device breakdown voltage, and hence power handling capability, is limited due to the band gap of the GaAs collector material. In this letter we will demonstrate for the first time that both of these limitations can be overcome through the use of InGaP. Since InGaP is not readily doped with carbon, it does not suffer from compensation due to carryover of carbon from the GaAs base. Hence, the ideality factor of the base‐emitter junction improves from 1.3 to 1.09 when the conventional n‐AlGaAs emitter layer is replaced with n‐InGaP. Moreover, InGaP eliminates the crossover of the base and collector currents typically observed in heavily carbon doped GaAs HBTs. This results in the maintenance of gain even at very low collector currents. As a collector material, we have found that InGaP produces significantly higher breakdown voltage than GaAs (19 V vs 12 V) of the same thickness and doping, due to its larger band gap. As in the emitter, InGaP collectors exhibit excellent ideality factors of ∼1.05.

58 citations


Journal ArticleDOI
Fan Ren1, Cammy R. Abernathy1, Stephen J. Pearton1, P. W. Wisk1, R. Esagui1 
TL;DR: In this paper, carbon-doped InGaP/GaAs single and double heterojunction bipolar transistors (HBTs) grown by gas-source metal organic molecular beam epitaxy (MOMBE) are reported.
Abstract: Carbon-doped based InGaP/GaAs single and double heterojunction bipolar transistors (HBTs) grown by gas-source metal organic molecular beam epitaxy (MOMBE) are reported. Large area devices (emitter diameter 70μm) exhibited gain of 25 for high injection levels at a base doping of 5 × 1019 cm-3. Ideality factors (<1.1) were obtained for both emitter-base and base-collector junctions in both single (SHBT) and double (DHBT) heterojunction devices. Vceos of 12 and 19V for SHBTs and DHBTs, respectively, were measured.

45 citations


Journal ArticleDOI
TL;DR: In this article, a diamond etch rate of 2000 A/min was obtained for 1 mtorr, 400 W O2 discharges with −80 V DC bias, and the etch rates increase with either pressure or microwave power as a result of a greater density of atomic oxygen in the plasma.
Abstract: Arc jet deposited films of diamond have been patterned using Au or photoresist masks and electron cyclotron resonance (ECR) O2 discharges. To achieve anisotropic features, additional RF-induced DC biasing of the sample is necessary. Diamond etch rates of 2000 A/min were obtained for 1 mtorr, 400 W O2 discharges with −80 V DC bias. The etch rates increase with either pressure or microwave power as a result of a greater density of atomic oxygen in the plasma. Chlorine (BCl3)-based discharges did not product significant etching of the diamond, but SF6/O2 mixtures had slightly faster rates than O2 alone.

37 citations


Book ChapterDOI
01 Jan 1992
TL;DR: In this article, the authors show that the luminescent efficiency of amorphous or polycrystalline Si improves upon hydrogenation, while there is a decrease in parameters such as reverse bias leakage currents in diode structures.
Abstract: Hydrogen is, in principle, the simplest impurity in semiconductor materials. It is a common constituent of many chemicals and gases used in the growth and processing of semiconductor crystals, and with its high diffusivity even near room temperature, hydrogen is readily incorporated into these materials. This incorporation is not always intended or even realized. The presence of hydrogen can be detected by direct means, such as mass spectrometry or ion-beam analysis, but in general its presence is betrayed by the changes it causes in the electrical and optical properties of the semiconductor. These changes are beneficial in disordered materials such as the amorphous [2.1] or polycrystalline [2.2] Si used to make solar cells. The addition of hydrogen in these cases acts to reduce the density of electrically active dangling bonds and dislocations, respectively, and the advances in solar-cell technology over the past two decades are due, in no small part, to the use of hydrogen passivation techniques [2.3]. The net effect of hydrogen incorporation in disordered semiconductors is to make them more like their ordered counterparts. That is, the luminescent efficiency of amorphous or polycrystalline Si improves upon hydrogenation, while there is a decrease in parameters such as reverse bias leakage currents in diode structures. These currents are usually dominated by defect-related processes such as generation-recombination and tunnelling.

37 citations


Journal ArticleDOI
TL;DR: In this paper, the carbon doping properties of GaAs grown by low pressure (30 Torr) organometallic vapor phase epitaxy at 520-700°C with CCl4 as the dopant precursor were compared for the four possible combinations of trimethylgallium (TMGa), triethyl gallium (TEGa), arsine (AsH3), and tertiarybutylarsine (TBAs).
Abstract: The carbon doping properties of GaAs grown by low pressure (30 Torr) organometallic vapor phase epitaxy at 520–700 °C with CCl4 as the dopant precursor were compared for the four possible combinations of trimethylgallium (TMGa), triethylgallium (TEGa), arsine (AsH3), and tertiarybutylarsine (TBAs). Secondary ion mass spectrometry (SIMS), Hall measurements, and infrared absorption were used to characterize the GaAs:C layers. Very high C‐doping concentrations (∼1020 cm−3) could be obtained using either TMGa or TEGa and AsH3. The use of TBAs instead of AsH3 led to a significant reduction in carbon incorporation, by approximately a factor of 5–10 per mole of As precursor over the growth temperature range examined. Hydrogen at significant concentrations (1–6×1019 cm−3) was detected by SIMS in GaAs: C layers grown at ≤550 °C utilizing all four combinations of Ga/As precursors. The existence of electrically inactive C‐H complexes was confirmed by observation of the C‐H stretching mode at 2635 cm−1. A post‐growth...

Journal ArticleDOI
TL;DR: In this article, the authors investigated the use of phenylarsine (PhAsH 2 ) and trisdimethylaminoarsenic (DMAAs) as potential replacements for AsH 3 during growth by chemical beam epitaxy (CBE).

Journal ArticleDOI
TL;DR: In this article, the effects of variations in pressure (1-20 mTorr), gas composition, and additional RF-induced bias on the sample were examined, with the etch rates found to be fastest with CH 4 addition, followed by H 2 and then Ar.
Abstract: Electron cyclotron resonance (ECR) discharges of HBr/Ar, HBr/H 2 , or HBr/CH 4 were used for dry etching of Ga-based (GaAs, GaSb, and AlGaAs) and In-based (InP, InAs, InSb, InGaAs, and InAlAs) III-V semiconductors. The effects of variations in pressure (1-20 mTorr), gas composition, and additional RF-induced bias on the sample were examined. At least -100 V of dc bias is required to initiate etching under all conditions, with the etch rates found to be fastest with CH 4 addition, followed by H 2 and then Ar

Journal ArticleDOI
C. Constantine, C. Barratt, Stephen J. Pearton1, Fan Ren1, J. R. Lothian1 
TL;DR: In this paper, high-rate (15 μm min−1) plasma etching of InP at 150°C with low additional DC bias (−150V) on the sample was demonstrated.
Abstract: Microwave (245GHz) Cl2/H2 discharges operated in the electron cyclotron resonance condition at low pressure (05 mtorr) are shown to yield high-rate (15 μm min−1) plasma etching of InP at 150°C with low additional DC bias (−150V) on the sample The etched surface morphology and optical quality, and anisotropy of the resultant features are all strong functions of the Cl2-to-H2 ratio in the discharge

Journal ArticleDOI
TL;DR: In this article, anisotropic dry etching of InP and p+ InP has been achieved at a fixed ratio of 10 HI/10 H2/5 Ar (total flow rate 25 sccm) and 1 mTorr pressure.
Abstract: Electron cyclotron resonance HI/H2Ar discharges with additional rf‐induced dc biasing of the sample have been used to obtain extremely anisotropic dry etching of InP. At a fixed ratio of 10 HI/10 H2/5 Ar (total flow rate 25 sccm) and 1 mTorr pressure, both n+ and p+ InP have etch rates of ∼875 A×min−1 at −100 V bias and ∼3000 A min−1 at −400 V bias. The etch rates increase rapidly with total discharge pressure, reaching 4000 A min−1 at 20 mTorr and −100 V dc bias. Rates in excess of 1 μm min−1 are obtained with higher HI flow rates or higher biases. Features 0.5 μm wide and 13 μm high have been etched, demonstrating the promise of this gas chemistry for production of laser mesas on InP and related materials with substantially faster etch rates (typically a factor of 8–10) relative to the more conventional CH4/H2 mixtures. The etched surfaces are smooth, with no evidence for iodine‐containing residues or preferential loss of either In or P. Both photoresist and SiO2 masks show minimal erosion in this mixture because of the ability to obtain practical etch rates at low pressure and low self‐bias.

Journal ArticleDOI
TL;DR: In this article, it was shown by spreading resistance and capacitance-voltage measurements that atomic hydrogen passivates shallow acceptors and donors in GaSb, and deep level passivation by hydrogen also occurs, as revealed by deep level transient spectroscopy measurements on Schottky diode structures.
Abstract: It is shown by spreading resistance and capacitance–voltage measurements that atomic hydrogen passivates shallow acceptors and donors in GaSb. Deep level passivation by hydrogen also occurs, as revealed by deep level transient spectroscopy measurements on Schottky diode structures. Effective diffusion coefficients for hydrogen were determined for both n+ and p+ GaSb; in the former case the diffusion is thermally activated with the relationship DH=3.4×10−5e−0.55 eV/kT, whereas in p+ material DH=1.5×10−6e−0.45 eV/kT over the temperature range 100–250 °C. Reactivation of passivated shallow and deep levels occurs for temperatures of 250–300 °C.

Journal ArticleDOI
TL;DR: In this article, the authors used self-bias during the etching of photoresist masks to minimize the effect of sidewall roughness on the underlying dielectric or semiconductor.
Abstract: Erosion and changes in the sidewall smoothness of masking layers commonly used as dry etch masks for III-V semiconductors have been studied for Cl2-, F2- and CH4/H2-based discharges. A particular problem with photoresist masks is the introduction of sidewall roughness which is transferred into the underlying dielectric or semiconductor. Distortion of the resist mask also occurs during high DC bias dry etching, leading to feature widths wider than the original mask dimension. Both of these phenomena are minimized with the use of low ( approximately 100 V DC) self-bias during the etching. Dielectric layers such as SiO2 display erosion and faceting of the mask edges during extended high-bias dry etching and for small ( 2 mu m) features into both GaAs and InP.

Journal ArticleDOI
TL;DR: In this article, a hybrid ECR-RF approach for etching of InP based devices in CH4/H2 plasmas and GaAs-based devices in CCl2F2 or PCl3 Plasmas is presented.
Abstract: Electron cyclotron resonance (ECR) discharges are characterized by high ion densities (

Journal ArticleDOI
TL;DR: In this article, the dissociation energies of Zn, Cd, and Mg-H complexes in p-InP have been determined from the reactivation kinetics of these passivated dopants in reverse-biased Au Schottky diodes.
Abstract: The dissociation energies of Zn‐H, Cd‐H, and Mg‐H complexes in p‐InP have been determined from the reactivation kinetics of these passivated dopants in reverse‐biased Au Schottky diodes. The reactivation process is first order under these conditions, yielding thermal dissociation energies of 1.20±0.10 eV for Zn acceptors, 1.40±0.10 eV for Cd acceptors, and 1.35±0.10 eV for Mg acceptors. These results are consistent with the model in which the hydrogen passivates the acceptor by attaching to a neighboring P atom, leaving the acceptor essentially threefold coordinated. They also indicate that acceptor‐hydrogen retrapping during cool down after epitaxial growth of p‐InP layers is the primary cause of apparently stable acceptor passivation seen in such layers.

Journal ArticleDOI
TL;DR: In this paper, a single energy, implant isolation scheme for thick (≥1.5 μm) III-V semiconductor device structures such as heterojunction bipolar transistors (HBTs) is described.
Abstract: A single‐energy, implant isolation scheme for thick (≥1.5 μm) III‐V semiconductor device structures such as heterojunction bipolar transistors (HBTs) is described. A 5‐MeV O+ implant at doses around 1015 cm−2 produces an almost uniform damage profile over ∼2 μm, sufficient to isolate structures containing highly doped (p=7×1019 cm−3) individual layers. The heavily damaged region associated with the end of the O+ ions range is placed in the underlying semi‐insulating substrate. Resistivities above 108 Ω/⧠ are obtained in GaAs/AlGaAs HBTs with such an implant, following annealing at ∼550 °C. High‐quality, 2×5 μm2 HBTs with gains of 25 for base doping of 7×1019 cm−3 have been fabricated using this isolation scheme. A considerable simplification is achieved over the use of conventional keV implants, where up to ten separate ion energies are required to isolate an HBT structure.

Journal ArticleDOI
TL;DR: In this article, the implant isolation characteristics of highly doped n− and p−type GaAs epitaxial layers implanted with 5 MeV O+ ions are reported, and high (∼108 Ω/⧠) sheet resistances are obtained in such layers following annealing at 550-600 °C for ion doses around 1015 cm−2.
Abstract: The implant isolation characteristics of highly doped n‐ and p‐type GaAs epitaxial layers implanted with 5 MeV O+ ions are reported. High (∼108 Ω/⧠) sheet resistances are obtained in such layers following annealing at 550–600 °C for ion doses around 1015 cm−2. The residual conductivity is still due to hopping processes with small activation (50–70 meV) energies. The use of a single MeV O+ implant considerably simplifies the isolation of GaAs/AlGaAs heterojunction bipolar transistor (HBT) structures relative to the usual multiple‐implant keV energy scheme. Small geometry (2×5 μm2) HBTs with gains of 25 for highly‐doped (p=7×1019 cm−3) base layer structures have been fabricated using MeV implant isolation.

Journal ArticleDOI
TL;DR: In this article, the authors describe the use of various plasma etching techniques in III-V semiconductor technology, which is consistent with an integrated processing concept in that plasma etch is a vacuum technique, and the dry etch reactor chamber can be coupled with other deposition, annealing or epitaxial growth chambers via load locks and transfer arms.

Journal ArticleDOI
TL;DR: In this article, an extensive study of the interfacial intermixing and interaction of the Pt/Ti bilayer metallization to seven III-V binary and related ternary compound semiconductor systems, as well as the contact electrical properties, are given.
Abstract: Results of an extensive study of the interfacial intermixing and interaction of the Pt/Ti bilayer metallization to seven III-V binary and related ternary compound semiconductor systems, as well as the contact electrical properties, are given. Pt/Ti contact to InAs and In/sub 0.53/Ga/sub 0.47/As were ohmic as deposited, while the same metallization scheme on GaAs, GaP, InP, In/sub 0.52/Al/sub 0.48/As, and Ga/sub 0.7/Al/sub 0.3/As provided a rectifying contact as-deposited. The latter group of contacts, with the exception of InP and GaP, were transformed to an ohmic contact as a result of rapid thermal processing (RTP) at the temperature range of 300 to 450 degrees C. A linear correlation between the semiconductor bandgap value and the Schottky-barrier height, measured in the Pt/Ti contacts, was observed. >

Journal ArticleDOI
TL;DR: In this article, the authors reported high performance selfaligned InGaP/GaAs HBTs using a base layer with a sheet resistance of 135 Ω/□, achieving a DC current gain of 25 for 2×5 μm2 devices.
Abstract: High performance selfaligned InGaP/GaAs HBTs are reported. SIMS and TEM analysis indicate the presence of clean and abrupt InGaP/GaAs interfaces which are reflected in excellent DC performance. Using a base layer with a sheet resistance of 135 Ω/□, a DC current gain of 25 was obtained for 2×5 μm2 devices. Both cutoff frequency ft and maximum frequency of oscillation fmax are measured above 70 GHz. These are the highest values yet reported for HBTs containing InGaP.


Journal ArticleDOI
TL;DR: In this article, a smart pixel prototype field effect transistor-self-electrooptic-effect device (FET-SEED) integrated optoelectronic amplifier was demonstrated.
Abstract: The authors have demonstrated a smart pixel prototype field-effect-transistor-self-electrooptic-effect-device (FET-SEED) integrated optoelectronic amplifier utilizing process technology suitable for flexible design and fabrication of high-yield optoelectronic circuits. A single MBE growth sequence provides for quantum-well modulators, photodiodes, doped channel MIS-like field-effect transistors (DMTs), and resistors. The device dimensions are controlled in a planar technology using ion implantation and selective plasma etching for isolation and contacting. Results demonstrate optical amplification in a fully integrated circuit. This technology will enable increased functionality by providing digital electronic processing between optical input and output. >

Journal ArticleDOI
TL;DR: In this paper, a universal etchant for III-V semiconductors was proposed and shown to give rise to highly anisotropic features with smooth surface morphologies at low dc Self bias (SBS) and low pressure (1 mTorr).
Abstract: In this paper HI/H{sub 2}/Ar discharges are shown to be universal etchants for III-V semiconductors, giving rise to highly anisotropic features with smooth surface morphologies. At low dc Self bias ({minus}V) and low pressure (1 mTorr), etch rates for all III-V materials of {gt}2000 {Angstrom} {center dot} min{sup {minus}1} are possible for high HI percentages in the discharges, whereas rates greater than 1 {mu}m {center dot} min{sup {minus}1} are obtained at higher pressures and dc biases. These etch rates are approximately an order of magnitude faster than for CH{sub 4}/H{sub 2}Ar mixtures under the same conditions and there is no polymer deposition on the mask or within the reactor chamber with HI/H{sub 2}/Ar. Auger electron spectroscopy reveals residue-free, stoichiometric surfaces after dry etching in this mixture. As a result, photoluminescent intensities from dry etched samples remain high with little apparent damage introduction. Changes in the near-surface carrier concentration due to hydrogen passivation effects are also negligible with HI-based mixtures in comparison to CH{sub 4}-based dry etching.

Journal ArticleDOI
TL;DR: In this article, the growth chemistry of MOMBE can be used to produce high speed GaAs/AlGaAs heterojunction bipolar transistors (HBTs) with high n-type doping.

Journal ArticleDOI
TL;DR: In this paper, double-heterojunction bipolar transistors (DHBTs) grown by organometallic vapour phase epitaxy (OPE) were used for the first successful fabrication of DHBTs for this material system.
Abstract: InGaP/GaAs single-heterojunction bipolar transistors (HBTs) and double-heterojunction bipolar transistors (DHBTs) grown by organometallic vapour phase epitaxy are reported. A current gain beta =40 was obtained for 90 mu m diameter HBT devices at a base-collector bias of 0 V. The base carbon-doping concentration for the devices was 2*1019 cm-3 and the sheet resistivity ( rho s) of the base layer was 600 Omega / Square Operator . For the DHBTs, a current gain beta =27 was obtained for a base-collector bias of 2 V. The carbon doping concentration in these devices was 8*1018 cm-3 with rho s=1400 Omega / Square Operator . This represents the first successful fabrication of DHBTs for this material system.

Journal ArticleDOI
TL;DR: Schottky barriers of Au, Al, and Sb on n and p-type layers of Al0.5Ga0.05Sb0.95 have been studied as discussed by the authors.
Abstract: Schottky barriers of Au, Al, and Sb on n‐ and p‐type layers of Al0.5Ga0.5As0.05Sb0.95 have been studied. The Schottky barriers are high for Au (1.3 eV) and Al (1.2 eV) deposited on n‐type material and very low for these metals on p‐type layers. The behavior of Sb is unique with the barrier heights being 0.6–0.7 eV for both n‐ and p‐type AlGaAsSb. The reason for the surface Fermi‐level pinning for Au and Al could be related to a predominance of Ga‐antisite–type native acceptors at the surface, which is not the case for Sb. Sulfur treatment of the surface is shown to decrease the barrier height for Au and to increase greatly the photosensitivity of Au Schottky diodes. The same effect is observed after treatment in a hydrogen plasma. In the latter case, changes in the Schottky barrier height are correlated with passivation of native acceptors in the bulk of the Al0.5Ga0.5As0.05Sb0.95.