Underfill for light emitting device

A light emitting device comprising:

• a light emitting chip disposed on a support surface;
• a plurality of bonding bumps disposed in a gap between the light emitting chip and the support surface, the plurality of bonding bumps providing at least one electrical power input path to the light emitting chip;
• and
• an underfill comprising underfill material disposed in the gap between the light emitting chip and the support surface, the underfill substantially filling the gap but not including a fillet extending outside the gap over sidewalls of the light emitting chip, the underfill providing at least one of (i) mechanical support for the light emitting chip and (ii) a thermal conduction path from the light emitting chip to the support surface;
• wherein the light emitting chip comprises:
• a plurality of epitaxial layers, the underfill not including a fillet extending outside the gap over sidewalls of the plurality of epitaxial layers, and
• a lattice-matched substrate on which the plurality of epitaxial layers is disposed, the plurality of epitaxial layers being lattice matched with the lattice matched substrate, the light emitting chip being flip chip bonded to the support by the plurality of bonding bumps such that the plurality of epitaxial layers is proximate to the support surface and the lattice matched substrate is distal from the support surface.