摘要:

The generation of high concentration defect‐related donor states during laser annealing of silicon with surface melting is found. Using these donors,p‐njunctions are fabricated onp‐type silicon substrate and good diode characteristics are obtained. Oxygen concentration increase in the laser annealed region is observed and suggests that the laser induced donors may be oxygen related. However, these donors are not oxygen thermal donors generally produced at moderate temperatures (<500 °C), because they are not annihilated by annealing at 650 °C. The present method provides for simple, low‐temperaturep‐njunction formation without the addition of dopants. This method will be applicable to device fabrication on processed wafers without disturbing pre‐existing device characteristics.

ISSN:0003-6951    

DOI:10.1063/1.96982

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

It is shown that the generation of interface traps by Fowler–Nordheim injection, like those generated by ionizing radiation, is a function of the mechanical strain at the silicon‐silicon dioxide interface. However, because of the current enhancement at the edge of a metal‐oxide‐semiconductor gate when the gate serves as the hot‐electron injector, this phenomenon may only be evident when the device is stressed with the gate biased positively. It is also shown that the capture rate of electrons in the silicon dioxide depends on the strain in the film.

ISSN:0003-6951    

DOI:10.1063/1.96983

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The kinetics of monocrystalline silicon oxidation using dry oxygen have been investigated over a wide range of pressure (14<P<1000 bars) within a low‐temperature domain (600<T<780 °C). In this unexplored domain, the linear and parabolic rate constants are dependent on the pressure asB/A∼P0.7andB∼P. The activation energy ofB/A(1.70 eV) is lower than the experimental values observed in conventional thermal oxidation. Very high residual stress values have been found for these oxides together with high values of refractive index suggesting that the oxidation proceeded under compressive in‐grown stresses.

ISSN:0003-6951    

DOI:10.1063/1.96984

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We have used local pseudopotentials with spin‐orbit coupling to illustrate some of the effects occurring in GaAs‐AlGaAs (001) superlattices as a result of fluctuations in the widths of the layers. Full account is taken of the microscopic superlattice potential, and states associated with the principal as well as secondary band minima are presented. It is shown that fluctuations of only one monolayer can lead to acompletetransfer of probability density into the lowest &Ggr;‐related symmetry‐induced state. This also applies to states associated with the secondary band minima confined in the hot‐electron range of energies. We also show that small fluctuations in layer width can be used to achieve a tunable spatial modulation of heavy‐ and light‐hole‐like character within thesamesuperlattice state. We discuss some of the implications of our results for band structure engineering.

ISSN:0003-6951    

DOI:10.1063/1.96985

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Crystal growth of InP on GaAs by vapor phase epitaxy is reported. It is demonstrated that good quality InP epitaxial layers with featureless surface morphology can be grown on GaAs substrate. Carrier concentration profile and Hall mobility measurements from as‐grownn‐type InP layers show that its doping behavior and mobility are similar to those grown on InP substrates. The results are encouraging for the development of devices utilizing InP/GaAs heterojunctions and the use of bulk GaAs as an alternative substrate to bulk InP for the epitaxial growth of InP and related compounds.

ISSN:0003-6951    

DOI:10.1063/1.96986

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Structures containing thin polycrystalline layers of W embedded in essentially single crystal GaAs have been grown by molecular beam epitaxy. The W layers exhibit resistivities of 90–300 &mgr;&OHgr; cm and Schottky barriers to both substrate and overgrown GaAs. The structures can act as metal gate transistors with &bgr; of 0.2–1.4 and &agr; of 0.4–0.6. These are the first reported metal gate transistors in the III‐V materials and the first using a nonepitaxial base and laterally seeded overgrowth. The use of a nonepitaxial base represents a degree of freedom which may be usefully exploited in a wide class of materials systems and may be important for the development of future metal gate transistors, especially in III‐V materials.

ISSN:0003-6951    

DOI:10.1063/1.96987

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We have studied the nucleation and propagation of threading dislocations in GaAs on Si epitaxial layers, and have found several techniques which are effective in reducing their density. The use of substrates properly tilted off (100) reduces the dislocation density as the presence of steps helps create perfect edge dislocations with their Burgers vector parallel to the interface and thus do not propagate into the bulk epitaxial layer. Cross sections by transmission electron microscopy show that the incorporation of an InGaAs/GaAs strained‐layer superlattice reduces the density of threading dislocations above it by a factor of 10, clearly demonstrating the effectiveness of this technique. These methods lead to a dislocation density of 103cm−2near the surface of 2 &mgr;m layers which is five orders of magnitude lower than what has been obtained previously. We have also found that the density of oval defects is much lower for GaAs on Si than for GaAs on GaAs.

ISSN:0003-6951    

DOI:10.1063/1.96988

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Etching of thin polyimide films in air was investigated using a line tunable, pulsed CO2laser. The threshold fluence for etching at a wavelength of 944 cm−1(10.6 &mgr;m) exceeds that at 1087 cm−1(9.2 &mgr;m) by a factor of 4. This is consistent with the infrared absorption spectrum which shows polyimide to be significantly more absorbing at 1087 cm−1. As a result, etching at 1087 cm−1produces a cleaner, more precisely defined region. Analysis of the vapors generated during laser etching shows the simple gases CO2, H2O, and CO to be present.

ISSN:0003-6951    

DOI:10.1063/1.96989

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

X‐ray photoelectron spectroscopy was used to analyze silicon surfaces after some standard cleaning procedures. Buffered hydrofluoric acid (BHF), RCA clean, and back door etch (BDE) result in less than one monolayer of suboxide coverage. RCA clean without BHF, heat treatment in nitrogen ambience, and prolonged explosure to air at room temperature all result in thicker self‐passivating suboxides. Wafers with arsenic ion implantation yield thicker oxides even immediately after BHF or BDE clean. Arsenic ion implantation also causes an additional chemical shift of 0.3 eV on the Si 2ppeak. The possible causes for these observations are discussed.

ISSN:0003-6951    

DOI:10.1063/1.96990

出版商:AIP    

年代:1986

数据来源: AIP