SURFACE CLEANING OF OPTICAL MATERIALS USING NOVEL VUV SOURCES

Directionally solidified Si/TaSi2 eutectic composites for the development of electronic devices (e.g. photodiodes and field-emission cathodes) were made using a Czochralski growth technique. High quality epitaxial growth of silicon on the eutectic composite substrates requires a clean silicon substrate surface prior to the growth process. Hence a preepitaxial surface cleaning step is highly desirable. The purpose of this paper is to investigate the effect of surface cleaning methods on the epilayer/substrate interface and the characterization of silicon epilayers grown on Si/TaSi2 substrates by TEM.Wafers were cut normal to the <111> growth axis of the silicon matrix from an approximately 1 cm diameter Si/TaSi2 composite boule. Four pre-treatments were employed to remove native oxide and other contaminants: 1) No treatment, 2) HF only; 3) HC1 only; and 4) both HF and HCl. The cross-sectional specimens for TEM study were prepared by cutting the bulk sample into sheets perpendicular to the TaSi2 fiber axes. The material was then prepared in the usual manner to produce samples having a thickness of 10μm. The final step was ion milling in Ar+ until breakthrough occurred. The TEM samples were then analyzed at 120 keV using the Philips EM400T.

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Book review: Optical Materials: an Introduced to Selection and Applications

IEE Proceedings J Optoelectronics ◽

10.1049/ip-j.1986.0021 ◽

1986 ◽

Vol 133 (2) ◽

pp. 134

Author(s):

C.R. Day

Keyword(s):

Optical Materials

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Structural/Property Relationships for Optical Materials

MRS Proceedings ◽

10.1557/proc-329-215 ◽

1993 ◽

Vol 329 ◽

Author(s):

Vivien D.

Keyword(s):

Crystal Structure ◽

Optical Properties ◽

Electronic Structure ◽

Chemical Composition ◽

Field Strength ◽

Optical Materials ◽

Site Occupancy ◽

Laser Materials ◽

Crystal Field Strength ◽

The Matrix

AbstractIn this paper the relationships between the crystal structure, chemical composition and electronic structure of laser materials, and their optical properties are discussed. A brief description is given of the different laser activators and of the influence of the matrix on laser characteristics in terms of crystal field strength, symmetry, covalency and phonon frequencies. The last part of the paper lays emphasis on the means to optimize the matrix-activator properties such as control of the oxidation state and site occupancy of the activator and influence of its concentration.

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