摘要:

The effects of rapid thermal oxidation (RTO) on the chemical vapor deposited nitride/oxide layer for thin gate dielectrics were studied. Successful growth of a top oxide of ∼25 A˚ was confirmed using x‐ray photoelectron spectroscopy and no punchthrough of the chemical vapor deposited nitride was observed for a nitride thickness of 60 A˚. Changes in electrical properties after RTO were studied using current‐voltage and charge‐to‐breakdown measurements. Results indicate that the top oxide reduces the leakage current under positive gate bias and increases the leakage current at high fields for negative gate bias. In addition, the charge to breakdown of the layer is increased after RTO.

ISSN:0003-6951    

DOI:10.1063/1.100942

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

GaAs/AlGaAs quantum wells (QWs) were grown by molecular beam epitaxy on GaAs (100) substrates patterned with ridges and grooves in the [011¯] direction. Low‐temperature cathodoluminescence was used to measure the Al fraction and QW thickness on top of the ridges and grooves as a function of ridge and groove width. Surface diffusion during growth depletes Ga from the side facets while increasing the incorporation of Ga on the (100) sections of ridges and grooves. The QW thickness on top of a ridge grown at 710 °C increases from 72 to 95 A˚, and the Al fractionxdecreases fromx=0.33 tox=0.29 as the ridge width is narrowed from 30 to 4 &mgr;m. Graded refractive index separate confinement heterostructure lasers with nominally 70 A˚ QWs and Al0.2Ga0.8As barriers were grown on patterned substrates at 695 and 725 °C. Lasers fabricated on the overgrown 4‐&mgr;m‐wide ridges have a 20 meV decrease in emission energy compared to laser diodes on 30 &mgr;m ridges.

ISSN:0003-6951    

DOI:10.1063/1.100943

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The interface structures of single quantum wells grown on vicinal (100) substrates with a controlled offset 0.2° are studied by cathodoluminescence microscopy. Bright and dark stripe patterns are periodically observed in monochromatic images of the single quantum wells and the stripes replicate stair‐like stepped interfaces. It is further shown that the observed terrace width is several times larger than the average interstep distance of monolayer steps calculated from the offset angle and that the step height is not one monolayer. Based on the results, a new interface structure model has been proposed that takes the offset angle into account. Finally, it is shown that employing growth interruption during epitaxial growth as an interface smoothing technique has limitations.

ISSN:0003-6951    

DOI:10.1063/1.100944

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We have determined the gap‐state profiles of phosphorus‐doped hydrogenated amorphous silicon before and after light soaking in a broader energy range [0.25–1.50 eV below the conduction‐band edge (Ec) ] by using several variations of isothermal capacitance transient spectroscopy. It is found that gap states are created in the range of 0.25–0.35 eV belowEc, which are attributed to31P‐related hyperfine electron‐spin‐resonance centers.

ISSN:0003-6951    

DOI:10.1063/1.100945

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Ultrathin InGaAs/InP single quantum well structures, grown by chloride transport vapor levitation epitaxy, have been investigated by low‐temperature photoluminescence (PL). Well‐resolved multiple peaks are observed in the PL spectra, instead of an expected single peak. We attribute this to monolayer (a0/2=2.93 A˚) variations in quantum well (QW) thickness. Separate peak positions for QW thicknesses corresponding to 2–6 monolayers have been determined, providing an unambiguous thickness calibration for spectral shifts due to quantum confinement. The PL peak corresponding to two monolayers occurs at 1.314 eV, corresponding to an energy shift of 524 meV. Experimental data agree very well with a simple effective mass theory.

ISSN:0003-6951    

DOI:10.1063/1.100946

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The Williams–Watts or stretched exponential decay of the formA(t)=exp[−(t/&tgr;)&bgr;] and variations of this form are compared to the capture and emission kinetics of theDXcenter observed by a number of authors. It is found that the time and temperature behavior of theDXcenter capture and emission characteristics can be reproduced with a thermally activated time constant &tgr; and a linear dependence of &bgr; on temperature. Activation energies, lattice vibration frequencies, and models of implicit distributions of activation energies are compared to values previously found in the literature. Consistency is found between parameters for both capture and emission, and implications of this model are discussed.

ISSN:0003-6951    

DOI:10.1063/1.100947

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Rapid thermal processing of implanted GaAs reveals a definitive sequence in the damage annealing and the electrical activation of ions. Removal of implantation‐induced damage and restoration of GaAs crystallinity occurs first. Irrespective of implanted species, at this stage the GaAs isn‐type and highly resistive with almost ideal values of electron mobility. Electrical activation is achieved next when, in a narrow anneal temperature window, the material becomesn‐ orp‐type, or remains semi‐insulating, commensurate to the chemical nature of the implanted ion. Such a two‐step sequence in the electrical doping of GaAs by ion implantation may be unique of GaAs and other compound semiconductors.

ISSN:0003-6951    

DOI:10.1063/1.100948

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Particle‐induced displacement damage effects in silicon bipolar transistors, including those due to electrons and to fission neutrons, are correlated on the basis of the nonionizing energy deposited in the lattice by the primary knock‐on atoms. Deviations from linearity between damage effects and energy deposition are in a direction opposite to those expected from defect cluster models but can be accounted for in terms of the fraction of vacancy‐interstitial pairs initially formed that survive recombination.

ISSN:0003-6951    

DOI:10.1063/1.100949

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We propose a mechanism which may shorten the gain recovery time in semiconductor optical amplifiers. The mechanism is carrier diffusion from nearby carrier storage regions (carrier reservoirs), which enhances the carrier recovery process in the active region and consequently reduces the gain recovery time. Bias‐independent recovery times as short at 100 ps are demonstrated in a 1.3‐&mgr;m traveling‐wave amplifier.

ISSN:0003-6951    

DOI:10.1063/1.100950

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We have investigated the transport properties of a two‐dimensional electron gas formed in delta‐doped In0.53Ga0.47As grown by metalorganic chemical vapor deposition technique. Very high free‐electron concentrations of 1.4×1013and 9.6×1012cm−2have been obtained at 300 and 77 K, respectively. Hall mobilities of 9300 and 14 600 cm2/V s were measured with carrier concentrations of 3.7×1012and 3.0×1012cm−2at 300 and 77 K, respectively. This is a factor of 3 higher than is expected for homogeneously doped materials having a similar doping. Schubnikov–de Haas oscillations confirmed the two‐dimensional nature of the electronic structure in these delta‐doped materials, and electron effective masses were determined from cyclotron resonance measurements.

ISSN:0003-6951    

DOI:10.1063/1.100951

出版商:AIP    

年代:1989

数据来源: AIP