Vertical cavity surface emitting lasers (VCSELs) and methods of making the
same are described. The VCSELs include reliability-enhancing layers that
perform specific functions at one or more critical locations within a
VCSEL structure to reduce or prevent defect formation and migration that
otherwise might degrade VCSEL performance, for example, by increasing
optical absorption in the mirror stacks or by degrading the electro-optic
properties of the active region. In particular, the reliability-enhancing
layers are configured to perform one or more of the following functions
within the VCSEL structure: gettering (i.e., removing defects or
impurities from critical regions), strain balancing (i.e., compensating
the lattice mismatch in the structure to minimize strain), and defect
suppression (i.e., creating alloys that reduce the formation of defects
during growth or post-growth activities). By strategically positioning one
or more appropriately configured reliability-enhancing layers with respect
to an identified defect source, the invention enables VCSEL structures to
be modified in a way that enhances the reliability and performance of
VCSEL devices.