摘要:

The oxidation of Be(0001), in particular the early stages of the reaction, was tracked dynamically by AES using a computer controlled single pass CMA. The reaction was followed by monitoring the three Auger transitions, Be(KVV), BeO(KVV), and O(KVV) indN/dEmode. Because the Be(KVV) and the BeO(KVV) signals overlap, a multiple linear regression analysis based on a linear combination of the spectra of clean, cleaved Be and a BeO crystal was done to separate them. Results have been obtained for oxygen partial pressures ranging from 4.7×10−7Pa (3.6×10−9Torr) to 1.3×10−4Pa. Considerable structure is seen in the uptake curves suggesting the occurrence of multiple stages of growth. The oxidation process appears to be linearly dependent on pressure for high pressures. Further conclusions are made difficult due to the strong enhancement of the oxidation by the AES incident electron beam. Finally, at all pressures studied, an excess of oxygen signal compared to that expected from stoichiometric BeO exists in the very early stage of the oxidation.

ISSN:0022-5355    

DOI:10.1116/1.571645

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

Mössbauer effect spectroscopy is applied to the analysis of the passive film on iron with the aim of supplying local site information. High count rate transmission experiments have been performed to examine the passive filminsituunder a variety of potentials. When electroplated, Fe‐57 enriched iron films are cathodically reduced at −350 mV RHE for over 1 h and then passivated at a potential of 1350 mV in a buffered borate solution pH 8.4, an isomer shift of 0.64±0.01 mm/s vs SNP and a quadrupole splitting of 1.14±0.09 mm/s for the passive layer are obtained. The isomer shift indicates iron present in the Fe+3valence state. The quadrupole splitting is larger than for bulk crystalline iron oxides, suggesting a disordered structure. MES data of cathodically reduced passive films show only pure iron, demonstrating complete reduction of the passive film. Spectra taken of a natural iron film passivated in an Fe‐57 containing borate solution indicate no contribution from iron precipitated from the solution. The resonant area associated with the passive film is observed to depend on specimen preparation, in particular, the amount of time spent during cathodic reduction prior to passivation. The isomer shift and quadrupole splitting are not greatly affected by changes in the passivating potential in the range from 1050 to 1550 mV RHE.

ISSN:0022-5355    

DOI:10.1116/1.571646

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

The surface and near surface composition of a single phase tin–lead alloy whose bulk composition was 99.83 at.% tin and 0.17 at.% lead has been measured as a function of temperature in vacuum and in an oxidizing ambient. In vacuum, the outer monolayer of the surface is enriched in lead at all temperatures studied (≊65% at.% Pb at 23 °C). From the measured lead surface composition as a function of temperature, a heat of segregation of 4.7 kcal/mole is calculated. The data obtained in an oxidizing ambient indicate that the near surface composition is dependent on the oxygen partial pressure as well as the temperature at which the sample is annealed.

ISSN:0022-5355    

DOI:10.1116/1.571647

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.571649

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

Semiconductor technology requires probably more sophisticated characterization techniques than any other modern technology. For example, many applications require atomic sensitivities of 1 ppb or less, and we may be interested in analyzing a volume smaller than 10−16cm3(hopefully not at the same time). In addition to elemental analysis of very small volumes, determination of the chemical state (oxidation state, etc.) of the constituents is many times critical. Of equal importance, especially for the high density of devices contemplated for very large‐scale integration, is the detection and characterization of defects present in wafer starting materials. Many techniques have been applied to these problems including Auger electron spectroscopy, x‐ray photoelectron spectroscopy, Rutherford backscattering, and secondary ion mass spectrometry. In this paper, I will describe the capabilities and limitations of these techniques for studies of important systems in semiconductor technology. The goal of this paper will be to provide the reader with the information necessary to choose among these techniques for a particular analysis application and to show how each can be applied in a complimentary fashion for a specific problem.

ISSN:0022-5355    

DOI:10.1116/1.571650

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

Auger depth profiling data are presented for thin films of silicon oxide grown by thermal oxidation and for thin films of silicon nitride and silicon oxynitride deposited by low pressure chemical vapor deposition. Samples are bombarded by 500 eV argon ions, and Auger data is collected in either theN(E) or thedN/dEmode of operation. By probing the N, O, and Si(KLL) peaks a quantitative analysis of these films has been made.

ISSN:0022-5355    

DOI:10.1116/1.571651

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

The present paper deals with experiments which indicate that vacuum devices with proper bakeout will remain at vacuum for several year periods when isolated from pumps and pumping.(AIP)

ISSN:0022-5355    

DOI:10.1116/1.571656

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

Increased present day use of cryogenics necessitates an understanding of the behavior of small leaks at liquid helium temperatures. Little is to be found in the literature except that related to super‐fluid effects in the range 1.4 to 2.9 K. We report the results of an investigation on the behavior of two small leaks (leak rates in the vicinity of 2×10−7atm cc air/s at room temperature) at 4.2 K in contact with gaseous as well as liquid helium. In both cases, a significant increase in the leak rate was found when the leaks were in contact with liquid helium at 4.2 K. The observed behavior is explained using a model based on the changes in the physical properties of helium with temperature.

ISSN:0022-5355    

DOI:10.1116/1.571657

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

The Sandia Laboratories Standards Department is currently using the comparison,PΔV, and accumulate‐dump methods to calibrate standard leaks. The comparison method may be used in the range from 10−5to 10−8atm cm3/s with a maximum uncertainty of 10%. ThePΔVmethod can be used for fundamental calibration of faster leaks in the range from 10−3to 10−5atm cm3/s with a maximum uncertainty of 5%. Finally the accumulate‐dump method can be used to fundamentally calibrate leaks in the range from 10−4to 10−10atm cm3/s with uncertainties ranging from 5 to 20%. The purpose of this paper is to introduce these three calibration methods with an analysis of the errors involved. These methods are reviewed and compared with other leak calibration methods.

ISSN:0022-5355    

DOI:10.1116/1.571658

出版商:American Vacuum Society    

年代:1982

数据来源: AIP

摘要:

The chemical and physical properties of the fluids employed in vacuum are given and the suitability of these fluids for various vacuum applications in relation to their properties are discussed. Techniques used for determining the suitability of fluids for vacuum use are indicated. Aspects of the above are illustrated by chemical formulas, mass spectra, and other experimental data such as oxidation resistance. The choice of fluids is discussed for the three applications of plasma processes (both deposition and etching), large pumping systems, and physical electronic applications such as electron microscopy, mass analysis, and spectroscopy. Finally, general aspects of vacuum fluids, their associated pumps, and auxiliary equipment are considered, for example: traps, pump maintenance, changing fluids, and the measurement of characteristics such as backstreaming.

ISSN:0022-5355    

DOI:10.1116/1.571660

出版商:American Vacuum Society    

年代:1982

数据来源: AIP