A novel superlattice (SL) design is proposed to improve the crystal quality in AlAs/InGaAs/InP resonant tunnelling diode (RTD) epitaxial structure. The ternary InGaAs well is substituted with binary InAs and GaAs layers in a periodic structure growth by MBE. The SL structure is compared with a standard equivalent ternary structure grown by MBE and one grown by MOVPE. Characterization by photoluminescence (PL) highlighted improvements in crystal uniformity