Hg1−xCdxTe, the evaporation is congruent. Films were deposited at different substrate temperatures in a Hg partial pressure. The as‐deposited films were stoichiometric and exhibit a strong 〈111〉 texture. As‐grown films are n‐type with electron mobility as high as 2×104 cm2/V‐s at 77 K.

Sputter profiling with Auger electron spectroscopy has been used to determine the depth profiles of Hg,Cd,Te, and O in anodic oxides on (Hg,Cd)Te in an effort to monitor the composition of the oxides and the properties of the oxide‐semiconductor interface. The measurements are straightforward, but the analysis and extraction of atomic concentration profiles are complicated due to nonstoichiometric erosion of the base material and possibly of the oxide. Conclusions from this and earlier investigations about the composition of the semiconductor past the interface are still dependent on a more basal understanding of the effects of low energy ion nombardment on (Hg,Cd)Te.

Kohler’s variational method is employed to calculate electron mobilities for n‐type Hg1−xCdxTe and CdTe. Scattering mechanisms considered include ionized and neutral impurity scattering, acoustic, piezoelectric, and optical phonon scattering, and disorder scattering. Ionized impurity cross‐sections are derived from the partial wave phase shift method, since use of the Born approximation can lead to significant error. Because the absence of carrier freeze‐out prevents an independent determination of compensation densities for Hg1−xCdxTe , a direct comparison with experiment is possible only for CdTe. In that case the agreement is relatively good down to about 30 K, but the theoretical values of mobility are greater than the measured values at the lowest temperatures. Similar behavior has already been observed in other semiconductors, and is probably due at least in part to the effects of multi‐ion scattering. The application of the phase shift method to p‐type Hg1−xCdxTe is also briefly considered. Criteria for the validity of the Born approximation and the single‐site scattering model are discussed.

A study was made of the Schottky barrier formation on cleaved n‐ and p‐type GaAs through surface and contact measurements. The metal used was silver. Surface studies, performed using the Kelvin method, have revealed that pinning of the Fermi level is obtained at submonolayer coverage and that silver deposition induced modifications in the electronic affinity. An electrical study of the contacts showed that diffusion barrier eVD is in the 950‐meV range for the n type and in the 270‐meV range for the p type. The difference between the pinning levels of n and p types for submonolayer coverage was found to be equal to that for contacts. We deduced that the Schottky barrier is established as soon as the first silver atoms are deposited. Possible characteristics were calculated for surface states (assumed to be discrete).

Ti and TiOx films have been made by vacuum and reactive evaporation, respectively, using electron beam heating. However, magnetron sputtering of Ti and its oxides is of interest because of the system’s simplicity and possible applications in the semiconductor and metallurgical industries. An investigation has been made into the discharge and deposition characteristics of a planar magnetron. Using a water-cooled Ti target operated at up to 1200 W in Ar and Ar+O2 mixtures, the results obtained show that V/I curves fall into two groups. Thus a high operating voltage is needed at either a low input power or high O2-gas content which is the characteristic mode for high oxidized film growth. High power inputs (even in the presence of a 25% O2 content) or low O2 content resulted in a low operating voltage and the growth of substantially metallic films. The effects of O2 on the discharge characteristic are briefly considered. Deposition rate curves as a function of power input for different gas mixtures are presented for these two growth modes. Also ’’phase diagrams’’ for both dc and rf power inputs are given which roughly classify the conditions needed to produce deposits tending to the metallic or oxide states. The film growth conditions for rf and dc magnetrons were similar but generally with rf a higher power input was needed to obtain metallic films and this was attributed to the reduced deposition efficiency of the rf system.

The Doublet III tokamak now in its fourth year of operation at General Atomic Company, has its plasma contained in a kidney-shaped toroidal vacuum vessel, a configuration that presented unique design challenges. Most tokamak vacuum vessels are constructed of solid walled sections separated by either thin walled bellows (to increase the toroidal resistance) or by poloidal insulation breaks. Such control of the toroidal resistance is crucial in minimizing magnetic error fields in the plasma region caused by currents induced in the vessel by the changing fields. The Doublet III vessel is unique in its all-welded construction consisting of thin skins over a corrugated center. Such a construction results in a low cross sectional area of material to increase the toroidal resistance, while maintaining adequate strength. The design process for such a vessel is reviewed with a description of its design. In order to more closely address the design issues of next generation devices, plans are being formulated to modify Doublet III to a large Dee-shaped plasma facility. This would be accomplished by disassembling the device and replacing the Doublet vessel with a large Dee vessel. The design approach for the new vessel will be similar to that of the present vessel, but because of different operating requirements and experience gained in the operation of Doublet III and other large tokamaks, the specific design criteria are different. These differences and their implications are reviewed.

A laboratory package, aimed at universities and technical institutes in developing countries, has been developed to provide a facility for training in vacuum technology. The package includes the construction and installation of all equipment, provision of a manual of experiments, and assistance in training the staff. The equipment consists of a rotary and diffusion pumped outfit, with numerous accessories, which are used to carry out 20 different experiments dealing with aspects of vacuum production and measurement. It is considered essential that the experiments convey information about widely used present‐day vacuum components and systems. A vacuum system, based on the single‐structure vapor pumping group and associated accessories, was especially designed to meet the requirements. Additional equipment is included to allow for more advanced projects dealing with vacuum applications. Experiments that are discussed fall into the following categories: operation of the rotary vane pump and vapor diffusion pump; vacuum measurement; leak detection techniques; some characteristics of the vacuum system; calibration of vacuum gauges; partial pressure gas analysis; thin film production and the monitoring of film thickness and evaporation rate; thin film preparation for electronic and optical applications; techniques for preparing electron microscopy specimens and freeze drying.

Boltzmann’s equation has been integrated for electrons describing trajectories in a radial electrostatic field (electron–electron and electron–residual‐gas interactions are neglected). One‐particle distribution functions are deduced for electrons describing, respectively, stable and unstable trajectories. Evolution of ionization efficiency of the device with various parameters is calculated using the preceding distributions. Experiments allow us to determine the integration constants and to validate theoretical predictions.

In chemical environments such as those encountered in the semiconductor industry it is important to specify a complete pumping system including pumps, accessories, oils, and an operating procedure. The paper discusses certain features of the pump design that are important in ensuring reliability when pumping aggressive materials. Further the accessories designed to augment the performance of the pump in aggressive situations are discussed with specific data on their performance under controlled conditions. Special attention is given to a range of oils and oil filtration methods, as in most cases it is the results of oil degradation and contamination that cause operating difficulties in aggressive atmospheres.

A method for depositing thin wear-resistant films onto spherical substrates is explained. Development of the technique is summarized including description of a special wear test on flats which simulates the spherical closed tribosystem. A unique sputtering machine designed to achieve uniform coatings on spheres and spherical cavities is also discussed.