摘要:

The preparation of stable thin films of controlled structure, composition, and thickness is a discipline bridging vacuum and materials sciences which has had significant effect on optics and electronics, although providing a limited number of working thin‐film substances. Techniques continue to be studied to extend the range of usable film materials on which thin‐film devices often depend for their development. Increasing use has been made in thin‐film technology of physical and chemical phenomena occurring in low‐pressure plasmas which are convenientinsitusources of activated gas and energetic ions to be applied as additional agents in film growth mechanisms. Thus ion extraction from plasmas for uniform doping during film growth is more likely to find wide use than ion implantation of solids. Energetic ions and/or activated species in ionized gas are now employed in processes forsurfacetreatment(nitriding),deposition(sputtering, ’’ion plating,’’ activated evaporation, plasma polymerization), and also foretching(sputtering, plasma etching). Although processes exist in which both physical and chemical effects are recognized to occur, treatment of the process mechanisms tends to be divided between two schools—one concerned withphysicaleffects such as ion impact sputtering and implantation, and the other withchemicaleffects arising from the release of reactive species in plasma‐activated gases. Experiments are described which show that the inner walls of a plasma reaction vessel acquire in the electrode region a negative potential to the plasma in excess of the floating value related to the random electron energy. Ions and electrons are accelerated in the positive ion sheaths which form at the walls of the vessel confining the plasma. Some recent experiments are described which demonstrate how reactive and energetic plasma components can interact. These studies show that (i) gaseous reaction products are more rapidly released from carbon in an O2‐plasma by ion impact, (ii) prevention of polymer growth on a surface by sputtering in a fluorocarbon gas plasma exposes the surface to more rapid attack by fluorine radicals, and (iii) energetic ion bombardment of degraded material during deposition on a target in a hydrocarbon gas plasma results in the growth of a carbon rich layer of unusual structure and properties.

ISSN:0022-5355    

DOI:10.1116/1.569159

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

摘要:

This paper reviews some defects of major importance in silicon substrates: their nature and geometrical distribution; the mechanism of formation; their interplays; and their implications. Topics discussed include swirl aggregates of point‐defect clusters and dislocation clusters; dislocations generated by thermal stresses; stacking faults generated by thermal oxidation both on the surface and in the bulk of substrates; and clustering and precipitation of oxygen.

ISSN:0022-5355    

DOI:10.1116/1.569117

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

摘要:

Conventional test methods to evaluate the quality of glass passivation overcoats on semiconductor devices are generally inadequate and/or destructive. We have recently devised three new methods that overcome these problems: (1) Sequential selective chemical etching of metal/dielectric structures to detect buried, latent, or partial defects as a function of dielectric layer depth. (2) Electrophoretic cell decoration with uv phosphor particles suspended in an insulating liquid, the sample forming one electrode of the cell. (3) Electrostatic corona charging to selectively deposit surface ions from a high‐voltage dc discharge on the insulating surfaces of the samples, followed by placing of the charged sample in a suspension of charged carbon black particles in an insulating liquid; depending on the polarity of the ions the particles can be deposited on the insulator surface or at the defect sites. The etching method is most suitable in process research studies, and the electrophoretic technique for demarcating relatively large defects. The corona‐decoration method, coupled with automated instrumental readout based on measuring the reflected‐light intensity, is ideal for routine testing of devices because it is fast, simple, sensitive, and nondestructive to devices such as glass‐passivated MOS and linear bipolar silicon‐integrated circuits.

ISSN:0022-5355    

DOI:10.1116/1.569201

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

摘要:

Metallic contamination present in silicon wafers prior to epitaxy or introduced during epitaxial processing were found to be responsible for microdefect formation in epitaxial silicon. Such contamination is often due to use of stainless‐steel tweezers. The defects as revealed by Secco etching appeared as shallow saucer pits (s‐pits). High densities of s‐pits were found to affect the surface carrier concentration of the epitaxial layer as measured by the high frequency MOS technique. The s‐pits were found to nucleate oxidation‐induced stacking faults (OSF) on (100) material during subsequent processing. Neutron activation analysis was used to identify the elements causing s‐pits, and transmission electron microscopy analysis was done to identify the defect as a dislocation loop. Several means of reducing s‐pit densities are also presented.

ISSN:0022-5355    

DOI:10.1116/1.569244

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

摘要:

Shrinkage and annihilation of oxidation‐induced stacking faults in silicon have been investigated by means of combined methods of successive annealing in nitrogen atmosphere and etching technique. The shrinkage rates were measured and the activation energies for shrinkage were determined to be 4.1 and 4.9 eV for (111) and (100) surfaces, respectively. Experimental results are interpreted in terms of climbing of a Frank loop, indicating that the shrinkage process is governed by a mechanism in connection with the self‐diffusion of silicon. A novel gettering technique is proposed.

ISSN:0022-5355    

DOI:10.1116/1.569260

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.569225

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.569239

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

摘要:

Silicates have been found to etch extrinsic silicon in a manner similar to hydroxides of alkali metals. Chemically simpler forms of silicates are strongly basic in nature and possess anisotropic properties when applied to Si masked by a defective glassy film. That is, they distinguish among the crystallographic planes in monocrystalline silicon. More complex forms of silicates, waterglasses in particular, do not show these properties. Because of the preferential character of silicon etching, the silicates pinpoint discontinuities in glassy passivation films. These etchants are applicable ton‐ andp‐type silicon in a wide range of resistivities. The advantage which the investigated silicates have over hydroxides of alkali metals is that they etch the glasses at considerably lower rates, which makes them suitable for destructive characterization of very thin passivation films.

ISSN:0022-5355    

DOI:10.1116/1.569241

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

摘要:

The crystallization process of chemically vapor deposited (CVD) amorphous Si films was studied by using a differential scanning calorimeter. A sharp exothermic peak due to amorphous–polycrystalline transition was obtained in the 665–700 °C range. The crystallization temperature was determined to be 665 °C. Transmission‐electron diffraction and transmission‐electron microscopic examinations revealed that, when amorphous Si film is heated at a slightly higher temperature than the crystallization temperature, the Si dendrite grains nucleate, and grow in size with heating time.

ISSN:0022-5355    

DOI:10.1116/1.569304

出版商:American Vacuum Society    

年代:1977

数据来源: AIP

摘要:

Heterojunctions have interesting optical properties which make them attractive for solar cells. Several types of heterostructure solar cells have been investigated: heteroface, abrupt heterojunction, and graded‐gap heterojunction solar cells. The primary advantage of heterostructure cells is the enhanced short‐wavelength response although there is potential for low‐cost cells with polycrystalline material. The improvement in solar‐cell performance for heterojunctions depends upon the selection of semiconductors with useful energy gaps that are closely matched in lattice‐spacing and thermal‐expansion coefficients. The importance of the heterojunction interface and its dependence on material properties is discussed. Various fabrication methods are discussed and their application to the different types of heterostructures. Recent performance data for material systems representative of each type of heterostructure cell are discussed and considered in terms of maximum expected performance.

ISSN:0022-5355    

DOI:10.1116/1.569153

出版商:American Vacuum Society    

年代:1977

数据来源: AIP