  Despite the superiority in quantum properties, self-assembled semiconductor
quantum dots face challenges in terms of scalable device integration because of
their random growth positions, originating from the Stranski-Krastanov growth
mode. Even with existing site-controlled growth techniques, for example,
nanohole or buried stressor concepts, a further lithography and etching step
with high spatial alignment requirements isnecessary to accurately integrate
QDs into the nanophotonic devices. Here, we report on the fabrication and
characterization of strain-induced site-controlled microcavities where
site-controlled quantum dots are positioned at the antinode of the optical mode
field in a self-aligned manner without the need of any further nano-processing.
We show that the Q-factor, mode volume, height, and the ellipticity of
site-controlled microcavities can be tailored by the size of an integrated
AlAs/Al2O3 buried stressor, with an opening ranging from 1 to 4 $\mu$m. Lasing
signatures, including super-linear input-output response, linewidth narrowing
near threshold, and gain competition above threshold, are observed for a
3.6-$\mu$m self-aligned cavity with a Q-factor of 18000. Furthermore, by
waiving the rather complex lateral nano-structuring usually performed during
the fabrication process of micropillar lasers and vertical-cavity surface
emitting lasers, quasi-planar site-controlled cavities exhibit no detrimental
effects of excitation power induced heating and thermal rollover. Our
straightforward deterministic nanofabrication concept of high-quality quantum
dot microcavities integrates seamlessly with the industrial-matured
manufacturing process and the buried-stressor techniques, paving the way for
exceptional scalability and straightforward manufacturing of high-\b{eta}
microlasers and bright quantum light sources.
