摘要:

In this letter, the electrical properties of thin low‐pressure chemical vapor deposited (LPCVD) SiO2annealed in N2O ambient have been studied and compared with thermal oxide of identical thickness. It is shown that N2O‐annealed CVD oxide exhibits less interface state generation and less flatband voltage shift under constant current stress than thermal oxide. It also has excellent uniformity and comparable breakdown characteristics. An oxynitride film formation at the Si/SiO2interface by annealing in N2O is speculated to be the cause of these improvements.

ISSN:0003-6951    

DOI:10.1063/1.105622

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The characteristics of W metallization for use as self‐aligned ohmic contacts and selective area etching and regrowth masks on InP‐based laser structures are reported. rf‐sputtered W films under either compressive or tensile stress were examined. Mesas for epitaxial regrowth were obtained by CF4/O2dry etching of the previously deposited W film, followed either by HBr/H2O2/H2O wet chemical etching or CH4/H2/Ar electron cyclotron resonance plasma etching of ∼4 &mgr;m of InP. The W film preserved its inert metallurgical nature while heated under PH3/H2ambient at 700 °C for 20 min, simulating the standard regrowth conditions. The W contacts onn‐InP (n=5×1018cm−3) substrates yielded stable, low contact resistivity (0.2 &OHgr; cm) after rapid thermal processing at 600–700 °C.

ISSN:0003-6951    

DOI:10.1063/1.105599

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The surface structure of polycrystalline Pt/Co multilayer thin films, sputter‐deposited on glass substrates with Ar, Kr, or Xe, was obtained with near‐atom resolution by scanning tunneling microscopy. Monatomic steps separating narrow terraces on the Ar‐sputtered films and large step‐like structures on the order of the Pt/Co bilayer thickness on the Xe‐sputtered films were observed. We attributed differences in surface features to bombardment of the growing film surface by reflected neutral inert gas atoms with different energy distributions. We correlated the observed surface structures with magnetic coercivity of these films.

ISSN:0003-6951    

DOI:10.1063/1.105600

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report for the first time aninsitudetermination of phosphorus compositions in a mixed group‐V compound, such as GaAs1−xPx, grown by gas‐source molecular beam epitaxy. Reflection high‐energy electron diffraction intensity oscillations from As‐limited and (As+P)‐limited growth are observed on a Ga‐rich GaAs surface. The phosphorus composition is therefore deduced from the different growth rates. Viability of this technique is strongly confirmed by the good agreement with the phosphorus compositions determinedexsituby x‐ray rocking curve measurements on GaAs/GaAsP strained‐layer superlattice structures.

ISSN:0003-6951    

DOI:10.1063/1.105601

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have studied chemical vapor deposited diamond films by scanning tunneling microscopy. The films have been prepared in a hot‐filament reactor. The gas, a mixture of 1% methane and 99% hydrogen, is fed into the reactor by a pulsed high pressure valve. Growth rates of 1.5 &mgr;m/h were obtained. The films are defined by scanning electron microscopy (SEM), Raman spectroscopy, and x‐ray diffraction. On a scale similar to those normally found in SEM micrographs a 110 texture is shown. On smaller scales amorphous structures with typical sizes less than 100 nm and individual equally sized clusters of approximately 5 nm in diameter are observed.

ISSN:0003-6951    

DOI:10.1063/1.105602

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Transistor action with both voltage and current gain exceeding 1 was observed in structures consisting of metal electrodes, insulating barriers, and high‐dielectric‐constant insulating SrTiO3. These structures were made on insulating (100) single‐crystal SrTiO3substrates having a dielectric constant of 2×104at 4.2 K. A Nb emitter and collector electrodes were placed on the substrates, with Si or SiO2barriers between the emitter and substrate. Base leads were made with silver paste on the back of the SrTiO3wafers. Devices both with and without barrier layers between the collector and substrate showed transistor action at 4.2 K. Essentially no current was required to control the collector current, which ranges from a few microamperes to a few milliamperes. For devices with a 30‐&mgr;m‐diam circular emitter having a minimum emitter‐collector spacing of 15 &mgr;m, the voltage gain was 2.5–4 and the maximum transconductance 1.4 mS.

ISSN:0003-6951    

DOI:10.1063/1.105576

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Polarization‐dependent photoluminescence (PL) and optical absorption spectra of (AlAs)1/2(GaAs)1/2and (Al0.5Ga0.5As)1/2(GaAs)1/2fractional layer superlattices (FLSs) were measured at room temperature. For the first time, it was observed that the spectra are dependent on their polarizations. The anisotropies in the PL and absorption spectra show that quantum confinement unambiguously occurs in the direction parallel to the surface, i.e.,lateralquantum carrier confinement effect appears. This finding proves that FLSs are promising for novel optical devices.

ISSN:0003-6951    

DOI:10.1063/1.105577

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Porous silicon/silicon structures under anodic oxidation conditions give rise to an electroluminescence phenomenon in the visible range. Using an optical multichannel analyzer the spectral distribution of the emitted light was measured−insitu−during the anodic oxidation step. Recorded spectra show a maximum which shifts continuously from red‐orange at the beginning of the process towards the yellow range. The visible emission well above the band gap of bulk silicon is attributed to a quantum size effect in the very small size (5–20 A˚) silicon island which constitutes the porous silicon skeleton. The light emission is interrupted when the current flow stops due to the formation of a continuous oxide layer at the porous silicon/silicon interface.

ISSN:0003-6951    

DOI:10.1063/1.105578

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have measured the deep level transient spectroscopy signal height of twoDXlevels usually observed inn‐type doped Al0.32Ga0.68As as a function of the filling pulse width. We report an overshoot in the capture transient of theDXlevel having a larger capture rate. We solve the rate equations for the capture processes of these twoDXlevels simultaneously. The capture transients thus obtained fit the experimental capture transients of these twoDXlevels reasonably well.

ISSN:0003-6951    

DOI:10.1063/1.105579

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We present results on room‐temperature photopumped lasing action in the blue region (∼4650 A˚) of the spectrum for double heterostructures with ZnSe active layers. The confining layers are ZnS0.06Se0.94, providing lattice match to the GaAs substrate. The room‐temperature lasing, observed under pulsed excitation, yields threshold pump intensity as low as 58 kW cm−2for an active layer thickness of 1500 A˚.

ISSN:0003-6951    

DOI:10.1063/1.105580

出版商:AIP    

年代:1991

数据来源: AIP