  Site-controlled growth of semiconductor quantum dots (QDs) represents a major
advancement to achieve scalable quantum technology platforms. One immediate
benefit is the deterministic integration of quantum emitters into optical
microcavities. However, site-controlled growth of QDs is usually achieved at
the cost of reduced optical quality. Here, we show that the buried-stressor
growth technique enables the realization of high-quality site-controlled QDs
with attractive optical and quantum optical properties. This is evidenced by
performing excitation power dependent resonance fluorescence experiments at
cryogenic temperatures showing QD emission linewidths down to 10 $\mu$eV.
Resonant excitation leads to the observation of the Mollow triplet under CW
excitation and enables coherent state preparation under pulsed excitation.
Under resonant $\pi$-pulse excitation we observe clean single photon emission
associated with $g^{(2)}(0)=0.12$ limited by non-ideal laser suppression.
