Formation kinetics of oxygen-hydrogen ͑O-H͒ complexes which give rise to an infrared absorption line at 1075.1 cm Ϫ1 have been studied in Czochralski-grown silicon crystals in the temperature range of 30-150°C. Hydrogen was incorporated into the crystals by high temperature ͑1200°C͒ in diffusion from H 2 gas. It was found that the observed kinetics can be explained as being due to an interaction of mobile neutral hydrogen-related species with bond-centered oxygen atoms. The binding energy of the O-H complex was determined to be 0.28Ϯ0.02 eV. An activation energy for migration of hydrogen-related species responsible for the formation of the O-H complexes was found to be 0.78Ϯ0.05 eV. It was shown that atomic hydrogen and H 2 *, a complex containing two hydrogen atoms, one at bond-centered site and another one at antibonding site, cannot account for the hydrogen-oxygen interaction considered. Hydrogen molecules (H 2 ) located at tetrahedral interstitial site are suggested to be the species which interact with interstitial oxygen atoms and form the complex giving rise to the absorption line at 1075.1 cm Ϫ1 .

The intensities of photoluminescence lines D1 through D4 and also of the background component that are characteristic in a dislocated silicon crystal are measured as a function of the temperature. All of them become weaker as the temperature is raised. Such behaviour is interpreted in a quantitative way with the model in which two different kinds of traps, one with a shallow level and the other with a deep level, participate in the radiative recombination process giving rise to each photoluminescence line. The shallower levels are assigned to the levels associated with hole traps that are drawn from the valence band by the deformation potential of a dislocation, and are in the range 4 to 12 meV above the top of the valence band. The deeper levels are proposed to be associated with electron traps due to the antibonding states of reconstructed bonds a t the dislocation core, being located in the range 0.16 to 0.35 eV below the bottom of the conduction band.Die Photolumineszenzintensitaten der Linien D1 bis D4 sowie der Untergrundkomponente, die charakteristisch ist fur einen versetzten Siliziumkristall, werden in Abhangigkeit von der Temperatur gemessen. Alle werden schwacher, wenn die Temperatur erhoht wird. Ein solches Verhalten wird quantitativ mit einem Model1 interpretiert, in dem zwei verschiedene Haftstellenarten, eins mit einem flachen Niveau und das andere mit tiefem Niveau, an dem strahlenden Rekombina-tionsprozeB teilnehmen und zu je einer Photolumineszenzlinie AnlaB geben. Die flacheren Niveaus werden den Niveaus zugeordnet, die mit Lochertraps verknupft sind, die aus dem Valenzband durch das Deformationspotential einer Versetzung stammen und im Bereich 4 bis 12 meV oberhalb der Valenzbandkante liegen. Fur die tieferen Niveaus wird angenommen, da13 sie verknupft sind mit Elektronenhaftstellen, hervorgerufen durch die antibindenden Zustande der rekonstruierenden Bindungen am Versetzungskern und im Bereich 0,16 bis 0,35 eV unterhalb der Leitungsbandkante lokalisiert sind.

Optical absorption of silicon crystals involving nitrogen and oxygen is investigated at low temperature. New absorption lines are found and attributed to seven defect levels that act as shallow donors. The characteristics of the absorption lines are well described by the effective mass approximation. Five among these seven levels are related to complexes of nitrogen and oxygen atoms.

By applying a new quenching method, we determined the formation energy of vacancies in high-purity silicon. Specimens were heated in H 2 gas at high temperatures for 1 h followed by quenching in water. By this method, vacancies are quenched in the form of complexes with hydrogen and the vacancy formation energy can be determined from the quenching temperature dependence of the intensity of the optical absorption peak due to the complexes. The vacancy formation energy of silicon was determined to be about 4.0 eV. This value is in good agreement with results of recent theoretical calculation.

Experimental results on the deformation of silicon crystals reported in a foregoing paper are discussed on the basis of a model and a hypothesis so far proposed. The dependence of the upper and the lower yield stresses on the temperature and the strain‐rate can be described reasonably well by the model of Haasen et al. Origins for some discrepancies between the results of the model and the experiments are discussed. The behaviour of the effective stress in the deformation stage after the middle of stage 0 is well described by the hypothesis of the steady state of deformation proposed by Sumino. The relation between the condition for the lower yield point and that for the steady state of deformation is discussed.