Optical semiconductor device and fabrication process thereof
AssigneesFujitsu Limited, Eudyna Devices Inc.
InventorsAyahito Uetake, Tatsuya Takeuchi
Life of this patent
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Abstract
An optical semiconductor, includes a semiconductor substrate having a (100) principal surface, a waveguide mesa stripe formed on a first region of the semiconductor substrate, the waveguide mesa stripe guiding a light therethrough; a plurality of dummy mesa patterns formed on the semiconductor substrate in a second region at a forward side of the first region, and a semi-insulating buried semiconductor layer formed on the semiconductor substrate so as to cover the first and second regions continuously, the semi-insulating buried semiconductor layer filling a right side and a left side of the waveguide mesa stripe in the first region and a gap between the plurality of dummy mesa patterns in the second region.
Claims16
An optical semiconductor device, comprising:
- a semiconductor substrate having a (100) principal surface;
- a waveguide mesa stripe formed on a first region of said semiconductor substrate, said waveguide mesa stripe guiding a light therethrough;
- a plurality of dummy mesa patterns formed on said semiconductor substrate in a second region at a forward side of said first region;
- and
- a semi-insulating buried semiconductor layer formed on said semiconductor substrate so as to cover said first and second regions continuously, said semi-insulating buried semiconductor layer filling a right side and a left side of said waveguide mesa stripe in said first region and a gap between said plurality of dummy mesa patterns in said second region.
A method for fabricating an optical semiconductor device, said optical semiconductor device comprising:
- a semiconductor substrate having a (100) principal surface;
- a waveguide mesa stripe formed on a first region of said semiconductor substrate, said waveguide mesa stripe guiding a light therethrough;
- and a plurality of dummy mesa patterns formed on said semiconductor substrate in a second region located at a forward side of said first region so as to extend in an extending direction of said waveguide mesa stripe, said method comprising the steps of:
- depositing a semi-insulating semiconductor layer on said semiconductor substrate by an MOCVD process so as to cover said first region and said second region continuously, such that said semi-insulating buried semiconductor layer fills, in said first region, a right side region and a left side region of said waveguide mesa stripe and such that said semi-insulating buried semiconductor layer fills, in said second region, a gap between said plurality of dummy mesa patterns,
- said step of depositing said semi-insulating buried semiconductor layer being conducted by adding an organic chlorine-containing substance such that there are formed flat regions in said first region along said waveguide mesa stripe respectively at said right and left regions of said mesa stripe with a flat surface at a level coincident to a top surface of said waveguide mesa stripe, and such that there are formed first and second sloped regions at respective outer sides of said flat regions with respective thicknesses decreasing with increasing distance from said waveguide mesa stripe,
- said step of depositing said semi-insulating buried semiconductor layer being further conducted such that, in said second region, said semi-insulating buried semiconductor layer fills said gap between said plurality of dummy mesa patterns with a thickness that does not become lower than a height of said plurality of dummy mesa patterns.
Dependencies are inferred from the claim text.