Nippon Telegraph and Telephone Corporation

Nippon Telegraph and Telephone Public Corporation

Hidefumi Mori

Jun-ichi Nakano

Fumihiko Kobayashi

Takeo Miyazawa

Mitsuo Yamamoto

Nobuyori Tsuzuki

Masahiro Ikeda

Tatsuo Izawa

Yasuji Murakami

Take Miyazawa

Nobuo Shimizu

An optical semiconductor device includes an optical semiconductor element, a semiconductor region, and a buried layer. The optical semiconductor element is formed on a semiconductor substrate. The semiconductor region opposes the optical semiconductor element and essentially surrounds the optical semiconductor element to form walls. The buried layer is arranged between the walls of the semiconductor region and the optical semiconductor element and formed by vapor phase epitaxy. In this optical semiconductor device, a distance between the wall of the semiconductor region and a side wall of the optical semiconductor element is larger in a portion in which the growth rate of the vapor phase epitaxy in a horizontal direction from the side wall of the optical semiconductor element and the wall of the semiconductor region is higher.

Optical semiconductor device and method of fabricating the same

Optical semiconductor device

In an epitaxial growth method of this invention, a first gas consisting of a hydrogen diluted gas containing a Group V element is continuously flowed on a monocrystalline substrate that is placed in a reaction chamber, the monocrystalline substrate is arranged in a gas mixing region where the first gas and a second gas containing a halogenide of a Group III element are mixed adjacent to the monocrystalline substrate, and a Group III-V compound semiconductor is grown on the monocrystalline substrate.

Epitaxial growth method and apparatus therefor

Method for halide VPE of III-V compound semiconductors

A thin film of a metal of which eutectic or compound is produced together with a semiconductor which is to be grown in its crystalline form is deposited on an amorphous (quartz glass) substrate. The thin film is patterned with a periodic pattern of a polygon having cross angles of multiples of about 60.degree., then the resulting substrate is heated at a temperature higher than the eutectic temperature of the metal and the semiconductor, and the semiconductor is deposited on the thin film under such heating condition, so that a crystalline film of the semiconductor is precipitated on the substrate. Such crystalline film is grown on a planar substrate at a low temperature of about eutectic temperature.

Method for manufacturing crystalline film

Halides of Si and Ti, B, P, or Ge and oxygen or steam are introduced into a reaction vessel and heated in a vapor phase to form fine glass particles by oxidation or hydrolysis. The fine glass particles are deposited on a substrate. The deposited fine glass particles are heated and vitrified into a transparent glass layer, which is etched to form a core having a desired pattern by a reactive sputter etching process using Freon gas. The core is coated by a clad. In a waveguide thus formed, the cross sectional configuration and dimensions of the core layer and the refractive index difference are precisely controlled. The waveguide is manufactured with good reproducibility. The fabrication method is suitable for mass production of waveguides. An expansion coefficient transient layer is provided between the core layer and the substrate to prevent a crack in the waveguide. The glass softening temperature of the cladding layer is set lower than that of the core layer, so that the cross sectional configuration and dimensions of the core layer is unchanged against the heat in the vitrification process of the cladding layer. The refractive index is reduced in the vicinity of the boundary between the core and clad to prevent the loss of light due to light scattering on the core side faces.

Method of making glass waveguide for optical circuit

Growing community of inventors

Tokyo, Japan

Hidefumi Mori