A mounting technology that increases the cw operating temperature of
intersubband lasers, without increasing the risk of hot spots near the
facets and short circuits near the perimeter of the laser chip, is
described. In accordance with one embodiment of our invention, a method of
fabricating a intersubband semiconductor laser comprises the steps of
providing a single crystal semiconductor substrate, forming on the
substrate an epitaxial region that includes a core region and an
intersubband active region in the core region, forming front and back
facets that define an optical cavity resonator, forming a metal electrode
on the epitaxial region so as to provide an electrical connection to said
active region, and mounting said laser on a heat sink, characterized in
that the mounting step includes the steps of (i) soldering the electrode
to the heat sink so that the front facet overhangs an edge of the heat
sink and (ii) cleaving off the overhanging portion of the laser so as to
form a new front facet that is essentially flush with the edge of said
heat sink. In accordance with another embodiment, our invention is further
characterized in that metal electrode to the epitaxial region is recessed
from the edges of the laser chip. In accordance with yet another
embodiment, our invention is further characterized in that the back facet
of the laser is coated so that any solder that might tend to creep onto
the back facet contacts the coating and not semiconductor material (in
particular the ends of the active region).