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Researchers Submit Patent Application, "Optical Semiconductor Device and Method of Manufacturing the Same", for Approval

February 26, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors HAYAKAWA, Akinori (Sagamihara, JP); Matsumoto, Takeshi (Hadano, JP), filed on July 17, 2013, was made available online on February 13, 2014.

No assignee for this patent application has been made.

News editors obtained the following quote from the background information supplied by the inventors: "Semiconductor lasers, which are optical semiconductor devices, have been widely used in various wavelength ranges. Among those semiconductor lasers, Distributed Feed-Back (DFB) lasers and Distributed Bragg Reflector (DBR) lasers have been used in communication applications and also used as a light source of an imaging device requiring a monochromatic laser. This is because those DFB and DBR lasers may lase in a single longitudinal mode.

"Moreover, reliability and service lifetime of a semiconductor laser are main factors to be considered when the semiconductor laser is put into practical use. In this regard, optical damage (which may be called Catastrophic Optical Damage (COD)) to an end surface of the semiconductor device may often become a major determinant factor for the service lifetime of the semiconductor lasers.

"Further, in a case where the maximum output and the like of the semiconductor laser is likely to be limited due to the COD thereof, if it is desired for the semiconductor device to output high power, it may be desired that the COD is controlled (reduced).

"Reference may be made to Japanese Laid-open Patent Publication Nos. 2001-230491, 2001-94207, and H09-23037."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "According to an aspect of the present invention, an optical semiconductor device includes a semiconductor substrate; a lower cladding layer formed over the semiconductor substrate and formed of a semiconductor material; a quantum well active layer formed on the lower cladding layer and formed of a semiconductor material; a diffraction grating layer formed over the quantum well active layer and formed of a semiconductor material, the diffraction grating layer having diffraction gratings formed in a surface thereof; and an upper cladding layer formed on the diffraction gratings of the diffraction grating layer.

"Further, a band gap in outer regions of the quantum well active layer that are adjacent to outer end surfaces of the optical semiconductor device is greater than a band gap in an inner region of the quantum well active layer that is located between the outer regions.

"Further, a thickness of one or more layers, which include the lower cladding layer and positioned between the semiconductor substrate and the quantum well active layer, is greater than or equal to 2.3 .mu.m.

"The objects and advantages of the embodiments disclosed herein will be realized and attained by means of the elements and combinations particularly pointed out in the claims.

"It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF DRAWINGS

"FIG. 1 is a top view of an optical semiconductor device according to a first embodiment;

"FIG. 2 is a first cut-away side view of the optical semiconductor device according to the first embodiment;

"FIG. 3 is a second cut-away side view of the optical semiconductor device according to the first embodiment;

"FIGS. 4A and 4B are first cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 5A and 5B are second cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 6A and 6B are third cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 7A and 7B are fourth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIG. 8 illustrates PL emission characteristics of a quantum well active layer;

"FIG. 9 is a correlation diagram between a thickness from a surface of a semiconductor substrate to a boundary of a quantum well active layer and band gap shift in the quantum well active layer;

"FIGS. 10A and 10B are fifth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 11A and 11B are sixth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 12A and 12B are seventh cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 13A and 13B are eighth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 14A and 14B are ninth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 15A and 15B are tenth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 16A and 16B are eleventh cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 17A and 17B are twelfth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 18A and 18B are thirteenth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIGS. 19A and 19B are fourteenth cut-away side views when the optical semiconductor device according to the first embodiment is manufactured;

"FIG. 20 is a top view of an optical semiconductor device according to a second embodiment; and

"FIG. 21 is a cut-away side view of the optical semiconductor device according to the second embodiment."

For additional information on this patent application, see: HAYAKAWA, Akinori; Matsumoto, Takeshi. Optical Semiconductor Device and Method of Manufacturing the Same. Filed July 17, 2013 and posted February 13, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4143&p=83&f=G&l=50&d=PG01&S1=20140206.PD.&OS=PD/20140206&RS=PD/20140206

Keywords for this news article include: Patents, Electronics, Semiconductor.

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Source: Electronics Newsweekly


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