摘要:

AbstractExtension and maximum concentration of autodoping profile are discussed for both lateral and vertical autodoping phenomena and, additionally, bearing in mind the typical course of autodoping profile as obtainable by spreading resistance technique, on the background of previously published theoretical concepts of dopant incorporation. It is shown that the “improved” (three‐step mechanism) as well as the “consequent” dopant incorporation concepts (two‐step mechanism) are suited for theoretically explaining autodoping phenomena. If no additional supposition will be stated, however, it is a consequence of the former that the concentration maximum in the profile of vertical autodoping equals the buried‐layer surface dopant concentration in agreement with non‐steady state layer doping behaviour after dopant source flow has been immediately interrupted. In the contrary the latter conception simply identifies lateral and vertical autodoping effect since autodoping above as well as beyond buried layer is controlled in the same way by parasitie dopant partial pres

ISSN:0232-1300    

DOI:10.1002/crat.2170240105

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractEpitaxial layers of GaAs have been grown by MOVPE using trimethylgallium‐trimethylamin‐adduct (TMGa‐TMN) as the Ga‐precursor. In comparison to the growth system using pure TMGa no significant influence on growth conditions and materials parameters could be found. The deposited GaAs is of fairly high quality with room temperature mobilities of 6700 cm2/Vs at free electron concentrations of about 1 × 1015cm−3. No hints to nitrogen incorporation coul

ISSN:0232-1300    

DOI:10.1002/crat.2170240106

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170240107

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe adsorption of silver on (110)tungsten was studied by a mass spectrometric molecular beam technique. The temporal behaviour of the flux of adatoms leaving the substrate was measured at fixed temperatures between 860 K and 1080 K for constant impinging rates over the range 0.2 · 1013to 9.0 · 1013cm−2s−1.For moderate supersaturation the growth mode changed from the layer‐by‐layer growth of three monolayers to the growth of three‐dimensional nuclei (Stranski‐Krastanov mechanism). At equal rates of impinging and desorption flux, the equilibrium adatom concentration was determined and a set of adsorption isotherms was thus derived. The shape of the experimental isotherms was found to be broadly similar to that of the theoretical Fowler‐Guggenheim isotherm for a localized adsorption model. The binding energy of an Ag atom to the substrate, the lateral binding energy of a pair of atoms, the coordination number, and the vibration frequency of the adatoms for all three monolayers were obtained by suitable fit

ISSN:0232-1300    

DOI:10.1002/crat.2170240108

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170240109

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe mechanism of the thermal behaviour of Na‐magadiite at a temperature range from 293–573 K was developed based on X‐ray diffraction, DTA, DTL, Q‐TG, and gravimetric measurements. A structure model (BRANDTet al.) previously proposed was additionally used.It is possible to show that there probably is a connection between the typical modifications of basal spacing and significant shiftings of silicate sheets. Different steps of dehydration, decrystallization and structure variations can be ascribed to the several thermal transitions. The results depend on sample treatment such as the existent or not existent solid‐water vapour interaction and the establishment of equilibrium. It seems that there is a predominance of the first mentioned

ISSN:0232-1300    

DOI:10.1002/crat.2170240110

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170240111

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe solvus of the NaCl: Pb2+system was found in the concentration range from 1.5 × 10−3to 1.9 × 10−2mol% at temperatures ranging from 375 to 430 °C from the data of flotation measurements of the crystal density. The heat of impurity dissolution equal to 2.0 ± ± 0.6 eV and the change in the vibrational entropy in the formation of the solid solutionSv/K= 20 ± 10 were determined.Reasons for a difference in the estimates of lead solubility in NaCl, obtained from temperature dependences of light scattering and by other methods: measurement of the density, electric conductivity, and the electron‐microscopic decoration of the same crystals ar

ISSN:0232-1300    

DOI:10.1002/crat.2170240112

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170240113

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe capabilities to study the geometrical construction of silicon devices by the technique of the electron beam induced current (EBIC) are reviewed with particular emphasis to the 2‐dimensional determination of dopant boundaries (p‐n junctions) including a discussion of demands for such investigations from a microelectronic point of view. The investigations of buried layers and MOS short‐channel transistors are outlined. As a substantial topic the preparation of electrically stable surfaces at cleaved samples is discussed and an example of the possibility of cross‐sectional analysis for junction delination is briefl

ISSN:0232-1300    

DOI:10.1002/crat.2170240114

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY