摘要:

A laser reflection technique is used to investigate the relaxation of SiO2film stress which occurs during the dry thermal oxidation of Si between 700 and 1000 °C. Included is a determination of the stress distribution in the oxide by two independent methods: (1) measurement on oxides of various thicknesses from 100 to 800 Å, and (2) repeated stress measurements on chemically thinned SiO2films, viz. etch‐back analysis toward the interface. Agreement is found between these experiments. These thin film stress measurements are achieved by the use of ultrathin Si substrates (75 μm). Essentially, an increase in film stress with decreasing film thickness is observed. Rapid stress relaxation is observed for all temperatures studied and is attributed to a time‐dependent oxide viscosity. The influence of these measured properties on the kinetics of Si oxidation is discussed.

ISSN:0734-211X    

DOI:10.1116/1.584402

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

A new method of preparing prepatterned contact resistance monitor wafers is presented that requires only two mask steps. After metalization, no masking, photolithography, or etching steps are needed to produce the three terminal structure. Because there is no photoresist bake, no Al–Si intermixing occurs and the wafer batch can be reclaimed prior to annealing if poor contacts were formed. The technique uses a standard low‐pressure epitaxial reactor to perform the selective silicon etching, leaving a SiO2overhang pattern to define the metal.

ISSN:0734-211X    

DOI:10.1116/1.584403

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

ISSN:0734-211X    

DOI:10.1116/1.584404

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Modified molecular‐beam epitaxy in which group V flux is suspended during 1 monolayer (ML) deposition of group III elements, is employed for growth of strained GaAs/InAs superlattices on InP substrates with a GaInAs buffer layer. By the reflection electron diffraction intensity study and by x‐ray photoelectron spectroscopy, the modification of growth procedure is shown to result in fast formation of a flat growth front without intermixing, which is necessary for superlattice growth. GaAs/InAs superlattice structures grown by the present method are characterized by x‐ray diffraction and transmission electron microscopy.

ISSN:0734-211X    

DOI:10.1116/1.584405

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

ISSN:0734-211X    

DOI:10.1116/1.584406

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

We report a new structure formed by δ doping the barrier of an AlGaAs heterostructure. Our structure contains a pair of electronically coupled quantum systems that develop from the quantum size effect occurring in the barrier and at the heterointerface. Compared to conventional homogeneous doping, we find enhancements in interface density resulting in δ‐doped structures for all spacer thicknesses. A mobility of 1.9×106cm2/V s is observed at a spacer layer thickness of 360 Å. Systematic dependences of interface mobility and density on spacer thickness are deduced from the quantum Hall effect and variable temperature Hall measurements.

ISSN:0734-211X    

DOI:10.1116/1.584407

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

ISSN:0734-211X    

DOI:10.1116/1.584409

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

ISSN:0734-211X    

DOI:10.1116/1.584410

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

During molecular‐beam epitaxy, growth interruption at each heterointerface of single quantum wells results in very narrow multiple peaks in photoluminescence (PL) spectra. These peaks correspond to extended monolayer‐flat regions of the wells, differing in well thickness by one monolayer. PL and PL‐excitation spectroscopies show that excitons tend to diffuse from narrower‐well regions to thicker‐well regions before radiative recombination takes place. This is also observed in time‐resolved PL. The intensity of the higher‐energy peak decreases with time, while that of the lower‐energy peak increases with time. The obtained exciton diffusion time of ≂250 ps is in good agreement with the estimated size (≤1 μm)of the monolayer‐flat islands from spectrally resolved cathodoluminescence.

ISSN:0734-211X    

DOI:10.1116/1.584411

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

ISSN:0734-211X    

DOI:10.1116/1.584412

出版商:American Vacuum Society    

年代:1988

数据来源: AIP