Ultra-thin in InAlP/InGaAs heterojunctins grown by metal-organic vapor-phase epitaxy

This paper reports the metal-organic vapor-phase epitaxy (MOVPE) growth of ultra-thin InAlP/InGaAs heterojunctions for use as wet-etching stoppers in InP-based high electron mobility transistors (HEMTs) and as barriers in resonant tunneling diodes (RTDs). InAlP/InGaAs modulation-doped (MD) heterojunctions with high electron mobility were successfully grown. Practical wet-etching selectivity in even 2-nm-thick InAlP etch stoppers was demonstrated. High peak current density (jP) of 5.4 times 10⁵ A/cm² with a peak-to-valley ratio (PVRs) of 1.6 was obtained in RTDs with 1.6-nm-thick In_0.75Al_0.25P barriers, which reflects the excellent abruptness and flatness of the heterointerfaces.