摘要:

Investigations with broad‐beam argon and reactive fluorinated ion beams have shown that the etched wall profiles of silicon at submicrometer linewidths can be controlled by varying the ion energy, current, and partial pressure of XeF2. Inert argon and reactive ion beams generated from xenon difluoride produced overcut profiles resulting from predominantly physical etching mechanisms. With very low partial pressures of XeF2in the background ambient, purely chemical etching of silicon is low while enhanced line‐on‐sight ion‐assisted etching can be used to produce vertical profiles. By increasing the background partial pressure of XeF2, undercut profiles were produced by purely chemical and chemically assisted ion beam mechanisms. Thus, various wall profiles were produced in silicon within the same broad‐beam ion etching equipment using the same two‐component gas system of Ar and XeF2.

ISSN:0003-6951    

DOI:10.1063/1.94274

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We have found a degradation of the buried crescent (BC) InGaAsP/InP lasers that occurs when thep‐njunction plane coincides with the surface exposed in the high‐temperature H2ambient before the melt contact during the liquid phase epitaxial growth. To eliminate the degradation, we have fabricated a new structure of the BC laser and have obtained stable cw operation at 80 °C.

ISSN:0003-6951    

DOI:10.1063/1.94275

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Surface ripples of submicrometer spatial period are observed in laser enhanced etching with liquid etchants. The surface ripple formation in the laser‐photochemical wet etching is not explained by the surface polariton model which needs melting of the semiconductor surface. To explain this ripple formation, we have to consider other mechanisms for ripple formation which does not need melting of the semiconductor surface, such as Raman excitation of surface polariton, polarization charge model, and bulk‐selvedge coupling model. We suggest that this low power and high speed laser‐photochemical etching provides a valuable one‐step process for producing the fine diffraction gratings required by integrated optics.

ISSN:0003-6951    

DOI:10.1063/1.94276

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We present a practical procedure for the evaluation of the Fermi energy in semi‐insulating (SI)GaAs from electrical measurements. This procedure makes it possible to reliably extend the determination of the major deep level (EL2) concentration, by near‐infrared absorption measurements, to SI GaAs. Employing this procedure, we showed that the EL2 concentration in Czochralski‐grown GaAs increases monotonically with increasing As/Ga ratio (throughout the conversion from SIntype to semiconductingp‐type crystals) rather than abruptly as previously proposed.

ISSN:0003-6951    

DOI:10.1063/1.94277

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The results of optical absorption measurements on fine‐grain polycrystalline‐silicon thin films indicate that the singly occupied dangling silicon bond lies 0.65±0.15 eV below the conduction‐band minimum in the grain boundary. The grain boundary band gap is ∼1.0 eV and there is evidence for exponential tailing of the band edges. The optical absorption was determined by photothermal deflection spectroscopy. The dangling silicon bond density has been measured on polycrystalline‐silicon thin films as a function of hydrogen passivation of the grain boundaries and on silicon‐on‐saphhire films. The optical absorption exhibits a defect shoulder which varies as the dangling bond density.

ISSN:0003-6951    

DOI:10.1063/1.94278

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The impact ionization process in the ⟨100⟩, ⟨110⟩, and ⟨111⟩ crystallographic directions in InP has been investigated by analysis of photomultiplication and multiplication noise data from InP avalanche photodiodes. This is the first report of such measurements for (110)‐oriented InP and the first consistent investigation of impact ionization in the three principal crystallographic directions. Our measurements indicate that, unlike the reports for GaAs, no significant orientation dependence of the impact ionization coefficients exists in InP. Momentum‐randomizing collisions with phonons, which result in intervalley transfer of energetic electrons, are believed to be the reason for the lack of anisotropy in the electron impact ionization coefficients.

ISSN:0003-6951    

DOI:10.1063/1.94279

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The electrochemical etching ofp‐CdTe is investigated. This etching is based on a method used previously for the selective etching ofn‐type Cd‐chalcogenide semiconductors. We show that the electrochemical etching creates a dense pattern of submicron pits, and increases the reverse bias photocurrent of a Schottky barrier device, made up of single crystalp‐CdTe and a polysulfide electrolyte typically by 20%. Evidence for the selective removal of surface defects is brought up and the conditions for selective etching are discussed in brief.

ISSN:0003-6951    

DOI:10.1063/1.94286

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Two new experiments are presented which suggest that the ‘‘bulk‐compensating donor’’ phenomenon observed inp‐Si is probably a deactivation process of the boron acceptor by hydrogen with the formation of a B−H+pair. The two experiments are (i) avalanche hole injection in Al‐gate metal‐oxide‐silicon capacitor from boron‐diffusedn‐Si substrate and (ii) 5‐keV electron irradiation of Al/p‐Si Schottky diodes. Atomic hydrogen may be released by the avalanche injected energetic electrons or holes or keV electrons from the Al–H, AlO–H, Si–H, and SiO–H sites in the Al gate and the SiO2film as well as at the Al/SiO2and SiO2/Si interfaces, which may then migrate to the boron acceptor sites to form the B−H+pair. Observed hydrogen bond breaking rate by holes is as much as two orders of magnitude larger than by electrons, which is consistent with the thermal hole capture and energetic electron impact bond‐breaking models.

ISSN:0003-6951    

DOI:10.1063/1.94287

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Subnanosecond photoconductive switching has been observed in ultraviolet illuminated type IIa diamonds. Switching efficiencies up to 50% were attainable in coaxially mounted samples for direct current bias voltage as high as 8 kV at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.94288

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The output voltage of a dc superconducting quantum interference device (SQUID) containing a resistive sectionRsoscillates at a frequency &ngr;q=Vs/ &fgr;0(&fgr;0=flux quantum) when a current controlled voltageVsis maintained acrossRs. These oscillations have been observed from ∼10−1to 1011Hz, usingRsvalues ranging from ∼10−10to ∼10−3&OHgr; in low inductance (∼10−10H) point contact SQUID loops. At high frequencies, they manifest themselves in the dc current‐voltage characteristics by inducing extra current steps.

ISSN:0003-6951    

DOI:10.1063/1.94258

出版商:AIP    

年代:1983

数据来源: AIP