Lu Taijing

Detection and characterization of microdefects and microprecipitates in Si wafers by Brewster angle illumination using an optical fiber system

Abstract Microdefects and microprecipitates were non-destructively detected in bulk and near surface of a Si wafer by Brewster angle illumination using an optical fiber system, because the p-component of the illumination enters completely into the wafer and then makes scattering from the defects while the other s-component reflects on the wafer surface so as to deviate from an objective lens for the detection of the scattering. Some results of observations and discussions will be done here about the scatterers in epitaxially grown Si layers, denuded zones of Si wafers, annealed amorphous SiC films, SIMOX specimens and slip bands in Si crystals.

Observation of microdefects and microprecipitates in Si crystals by IR scattering tomography

Abstract A new instrument of IR light scattering tomography (LST) with an excellent image processing software (MILSA) has been developed for non-destructive detection of microdefects and microprecipitates in semiconductor crystals. Using LST with MILSA the growth striations, denuded zone layers and microprecipitates as well as oxidation induced stacking faults in silicon crystals were detected clearly and correctly by a beam from a YAG laser.

Temperature evolution of domains in potassium niobate single crystals

The behavior of domain walls in KNbO3 single crystals with temperature variation from room temperature to 300 °C has been investigated in situ by a heating visualization system. It has been observed that domain walls show active behavior in a small temperature range from the phase transition temperature of 225 °C, the range being about 10 °C in the orthorhombic phase and 15 °C in the tetragonal phase. The 90° domain walls are generated randomly and extend themselves rapidly within the crystal in high density. The 60° domain walls, which are only observed in orthorhombic phase, do not appear randomly but are formed along the boundary of intersecting 90° domain walls. The results suggest that the 90° domain walls are most likely caused by microdefects within the crystal, and that dislocations at the junction of intersecting 90° domain walls supply nucleation sites for the 60° domain walls.

Dependence of charging on crystallographic orientations of an as‐grown α‐quartz

The scanning electron microscope copper‐detector technique introduced most recently by H. Gong and C. K. Ong [J. Appl. Phys. 75, 449 (1994)] is employed for the investigation of charging on faces m {1010}, R {1011}, and χ {5161} of single‐crystalline α‐quartz. It is found that the charging ability decreases in the order of m, R, and χ, revealing the dependence of charging on crystallographic orientations, and these results are confirmed by the well‐established mirror‐image method. In addition, the experimental results also suggest that not only electron‐irradiation‐induced defects but also intrinsic defects are responsible for charge trapping.

Effects of impurity concentration on dielectric loss in Zn‐doped InP at microwave X‐band frequencies

Microwave dielectric measurements have been performed on various Zn‐doped InP crystals using a vector network analyzer. There are two kinds of dielectric response in Zn‐doped InP crystals depending on their Zn concentration. The general dielectric response in InP in the microwave frequency region is dielectric relaxation, which is related to the dipolar species formed from the ionized substitutional ZnIn−. The other dielectric response of InP crystals doped with a higher Zn concentration is dielectric loss. The crystal doped with Zn to a concentration of 2.14×1018 cm−3 shows a strong dielectric loss at 11 GHz, but no dielectric loss peaks are found in crystals doped with a lower Zn concentration of 4.36×1017 cm−3. The dipolar species, which gives rise to the dielectric loss in Zn‐doped InP crystals, is believed to be a result of vacancy complex defects of neutral substitutional ZnIn and two P vacancies.

Size distribution of ultrafine particles in KDP aqueous solutions

Quantitative and qualitative investigations on the size distribution of ultrafine particles in KDP solutions were performed by a laser light scanning particle counter and by comparing with scattering polystyrene particles of standard size. The ultrafine particles are of a size distribution from 1000 nm. The size of the visual particles, which are distinguished individually by a laser light-scattering technique, 3 was estimated in the size range from 200 nm to 1000 nm. The reliability of the results was evaluated.

MICROWAVE DIELECTRIC RESONANCE OF A FLUORIDE GLASS

The dielectric properties of a fluorozirconate glass are investigated in the frequency range from 0.5 to 13.5 GHz using a microwave vector network analyzer. A prominent dielectric resonance is observed around 7.0 GHz. The resonance may be due to a fundamental interunit vibrational mode of the basic structural ZrFn polyhedral units of the fluorozirconate glass.

Detection of oxidation stacking faults in silicon wafers by a multipass Fabry-Perot Rayleigh-Brillouin scattering spectrometer

Abstract The ring-bands of oxidation stacking faults (OSFs) in silicon wafers were detected nondestructively using a multipass Fabry-Perot Rayleigh-Brillouin scattering spectrometer.

New Interference Fringes Generated by Epitaxial Layers of Semiconductors and SIMOX (Oxygen-Ion-Implanted-Si) Wafers

Truly new interference fringes generated by SIMOX (oxygen-ion-implanted silicon) wafers and hetero-epitaxial layers of semiconductors were originally and clearly observed. Generation of the new fringes was caused by interference between a part of the incident light pencil reflected from the top surface of a specimen and the light scattered from the hetero-interface after refraction of the other part of the pencil. The reflection from the top surface is fairly large due to the very high refractive index (more than 25% at most semiconductor surfaces) and the intensity of light scattered from the interface is strong enough for it to act as a plane source with coherency.

Characterization of striations in silicon wafers by a multipass Fabry-Pérot Rayleigh-Brillouin scattering spectrometer

Swirls and oxidation stacking faults (OSF) ring-bands in the near surface region of Si crystals have been detected and characterized by a 180°backscattering Rayleigh-Brillouin spectrometer using an argon-ion laser as its light source. In FZ Si wafers with swirls, the central region exhibits high scattered light with random undulation, the peripheral region with swirls shows a periodic undulation of scattered light intensity, while the region in-between is a nearly uniform zone of low scattered light intensity. In contrast to this, the CZ Si wafers with OSF ring-bands display a low uniformly scattered light background with a high undulated scattered light zone corresponding to the OSF ring-band. The scattered light intensity and its structure in the OSF ring-band vary with the heat-treatment conditions. The features of scattered light detected by the scattering spectrometer are discussed.