Laser chip for flip-chip bonding on silicon photonics chips

A method for bonding a laser chip on a silicon photonics chip with enhanced 3D alignment precision and tolerance comprising:

• providing a laser chip including forming a chip body with an active region buried between a p-region and a n-region in vertical direction and extended from a front facet to a rear facet in longitudinal direction, forming a pair of first vertical stoppers located beyond respective two sides of the chip body, forming a first alignment mark in the longitudinal direction in a top surface of the p-region near the front facet defined with a lateral distance in sub-micron precision relative to a vertical projection line of the active region in the top surface of the p-region, and forming a thin metal film having a cleaved edge matching with the front facet;
• setting up a chip-site in a recessed surface of the silicon photonics chip having a waveguide port located at a height above the recessed surface, the chip-site including a pair of second vertical stoppers stood on the recessed surface and a second alignment mark in the recessed surface with a lateral distance defined in sub-micron precision relative to a vertical projection line of the waveguide port in the recessed surface;
• bonding the laser chip with the top surface of the p-region facing down via a solder material to the chip-site in the recessed surface with the pair of first vertical stoppers respectively joining with the pair of second vertical stoppers for determining vertical alignment between the active region and the waveguide port;
• determining lateral alignment by aligning the first alignment mark to the second alignment mark;
• and
• determining longitudinal alignment by identifying the front facet based on reflection contrast at the cleaved edge of the thin metal film.

A laser chip for flip-chip bonding on a silicon photonics chip with enhanced passive alignment features comprising:

• a chip body made of a p-region and a n-region in vertical direction and extended from a front facet to a rear facet in longitudinal direction;
• a pair of first vertical stoppers formed respectively beyond two sides of the chip body;
• an active region in a linear shape buried in the chip body between the p-region and the n-region in the vertical direction and extended from the front facet to the rear facet in the longitudinal direction;
• and
• a first alignment mark in the longitudinal direction formed on a top surface of the p-region near the front facet with a lateral distance defined in sub-micron precision relative to a vertical projection line of the active region in the top surface of the p-region.

A laser chip for flip-chip bonding on a silicon photonics chip with enhanced passive alignment features comprising:

• a chip body made of a p-region and a n-region in vertical direction and extended from a front facet to a rear facet in longitudinal direction;
• an active region in a linear shape buried in the chip body between the p-region and the n-region in the vertical direction and extended from the front facet to the rear facet in the longitudinal direction;
• a first alignment mark in the longitudinal direction formed on a top surface of the p-region near the front facet with a lateral distance defined in sub-micron precision relative to a vertical projection line of the active region in the top surface of the p-region;
• and
• a thin metal film on the surface of the p-region having a cleaved edge shared with the front facet.