Paramorphic Growth: A New Approach in Mismatched Heteroepitaxy to Prepare Fully Relaxed Materials

We propose paramorphic growth as a new approach for growing thick, ideally relaxed, epitaxial layers on mismatched substrates. First, a thin seed layer, originally grown pseudomorphically strained on a mismatched substrate coated with a sacrificial layer, is separated by chemical etching from its original substrate and subsequently deposited on the final substrate after being elastically relaxed. Consequently, thick layers, lattice matched to the cubic-relaxed seed layer, can be grown epitaxially without the introduction of any structural defects. The validity of this approach is demonstrated by growing fully relaxed In 0.65 Ga 0.35 As thick layers on 300×300 µm 2 platforms deposited on an InP substrate, using molecular beam epitaxy.