Epitaxial lift-off of II–VI semiconductors from III–V substrates using a MgS release layer

Abstract

Epitaxial lift-off (ELO) is a post-growth process that allows an epitaxial layer to be removed from its original substrate and transferred to a new one. ELO has previously been successfully demonstrated for III–V materials and also ZnSe based II–VI semiconductors using a MgS sacrificial layer. Following the recent successful growth of epitaxial MgS layers on GaP and InP substrates, in this paper we compare ELO of II–VI epilayers grown on GaP, GaAs, and InP substrates using MgS sacrificial layers in the range of 7–15 nm thick. Good quality lifted layers are obtained rapidly from InP and GaAs substrates. For GaP substrates, ELO is much slower and good quality lifts have only been achieved with ZnSe epilayers. Photoluminescence spectra obtained from epitaxial layers before and after ELO show changes in peak positions, which are compatible with changes of strain in the layer. The layers produced by ELO are flat and free of cracks, suggesting that this is an efficient and convenient method for the transfer of II–VI epitaxial layers to other substrates.

Stacking of ZnSe/ZnCdSe Multi-Quantum Wells on GaAs (100) by Epitaxial Lift-Off

“…XRI was also used to determine the QW composition as Zn (0.79) Cd (0.21) Se. 5 An initial ZnSe buffer layer is used to protect the substrate from S contamination and provides the best surface for the growth of MgS sacrificial layer. 4,8 The normal ZnSe 2 9 1 and MgS C (2 9 2) reflection high-energy electron diffraction (RHEED) patterns 9 were observed during both layer growths.…”

“…4 We recently extended II-VI ELO to the three main commercially available III-V substrates, still using MgS as the sacrificial layer. 5,6 Studies recently have focused on combining semiconductor structures using novel post-growth processing such as direct wafer bonding to overcome some inherent growth or material limitations. 7 This process showed that two different semiconductor layers can be combined together in one structure.…”

Adhesion Measurements of Epitaxially Lifted MBE-Grown ZnSe

“…2 We have shown that II-VI layers grown on GaAs, InP, and GaP can all be exfoliated using this technique. 3 ELO layers have been successfully transferred to alternative substrates such as glass, laser diodes, 4 distributed Bragg reflectors (DBRs), 5 and LiNbO 3 . 6 While fabricating these and other devices, it was observed that the adhesion of the lifted layer varied according to the alternative substrate material chosen.…”