Abstract A recent development of Molecular Beam Epitaxy (MBE) — the Atomic Layer Molecular Beam Epitaxy — has been used to grow AlAs InAs strained layer superlattices (SLS) on (001)GaAs at low growth temperatures (T s < 400°C). The growth process basically consists on alternating group V and/or group III beams following an optimum timing established by RHEED oscillations observation during the monolayer formation sequence. This method allows to grow at low substrate temperature with excellent morphology, even for those systems which have extremely different optimum MBE growth conditions and a severe lattice mismatch of 7% like AlAs InAs . X-ray diffraction and optical characterization results for superlattices of different periodicities are presented. In particular, Raman spectra of these samples showing folded acoustic phonons demonstrate their quality.