Infrared spectroscopy was performed on a thin section of a chalcedonic quartz at high temperature in order to investigate the states and diffusivity of intergranular water. The sample contained 0.3 wt.% of silanol (Si—OH) and 0.3 wt.% of molecular H2O, located mainly at intergranular regions but also as fluid inclusions. We monitored the diffusion of molecular H2O associated with dehydration by in situ analyses at 350—500°C and determined the bulk-diffusion coefficients as expressed by an Arrhenius relationship: Dbulk (m2 sec—1) = 10—4.5 exp(—107±17/RT), where R is the gas coefficient and T the temperature. The activation energy for our sample is similar to those previously reported for diffusion in quartz aggregates with incompletely-connected grain boundaries. This result and our previous measurements of electrical conductivity imply that diffusion of molecular H2O at incompletely- connected intergranular regions is the main mechanism for the dehydration. The diffusion coefficients in chalcedony are larger than those previously reported for rhyolitic glass and other granular aggregates. Intergranular regions, inherent larger pores and cracks created during heating can act as efficient diffusion paths within the chalcedony.

Noncontact laser/microwave deep level transient spectroscopy (LM-DLTS) based on the measurement of microwave reflection power as a function of temperature has been developed and applied to Czochralski silicon crystals intentionally contaminated with selected metals during crystal growth. The energy levels related to these metallic impurities in p-type silicon have been obtained on bare silicon for the first time without any electrode contact or special sample preparation. The data agree in very satisfactory fashion with results obtained by conventional DLTS.

This paper discusses the temperature dependence of recombination lifetime in a variety of silicon materials using energy level as a parameter. A theoretical approach based on the Shockley-Read-Hall theory for energy level calculations has been used. Various types of defects created by introducing impurities, dislocations and grain boundaries into silicon wafers were studied. Results are presented for Czochralski grown Si wafers intentionally contaminated with gold and chromium, EFG ribbon with varying concentration of oxygen, web ribbons with extended defects and contaminants, large grain polycrystalline material, and Si/Si-Ge/Si heterostructures with varying misfit and threading dislocation density. INTRODUCTIONMinority carrier recombination lifetime is a convenient parameter for semiconductor material evaluation, since it is significantly affected by defect-induced traps located within the forbidden gap. The recombination depends not only on the energy level location, but also on the trap concentration and capture cross section. Therefore, in order to describe accurately the recombination behavior of defects, these three components have to be characterized. A commonly used technique for this purpose is deep level transient spectroscopy (DLTS) [1]. Although this technique is very powerful, it is relatively complicated, time consuming and requires some sample preparation. However, in many cases determining the recombination lifetime and the activation energy of a specific defect or impurity is sufficient enough to evaluate material quality. For this purpose only the temperature dependence of recombination lifetime 'r(T) is required. This dependence can be obtained with contactless, high throughput and nondestructive techniques for which no device fabrication is required. This paper discusses the 'r (T) dependence in a variety of silicon materials using defect energy level as a parameter. A theoretical approach based on the Shockley-Read-Hall theory for energy level calculations has been used. Various types of defects created by introducing metal impurities, grain boundaries or misfit dislocations into Si wafers were studied. A laser / microwave DLTS technique (LM-DLTS) [2] operating in the temperature range from 273 K to 523 K was used as a non destructive, contactless tool for lifetime and activation energy determination of bare non-processed silicon.

Minority-carrier recombination lifetime has been measured with a noncontact laser/microwave method for magnetic field applied Czochralski silicon crystals in the temperature range from 20 to 250 °C. The lifetime behavior in both as-grown and heat treated silicon crystals strongly depends on the thermal history of the samples. It is shown that the lifetime measurement is very sensitive to grown-in and thermally induced defects which cannot be detected by conventional infrared absorption spectroscopy or transmission electron microscopy.