Implant-damage isolation of InP and InGaAsP

Abstract

The creation of high resistivity layers by ion implantation of doped InP and InGaAsP epilayers, and the potential of the implant-isolation technique for the fabrication of InP-based ridge waveguide lasers, have been investigated. InP and InGaAsP samples, doped with 5×1017 cm−3 Si or Zn, were implanted with multiple-energy 4He or 16O. Ridge waveguide lasers, with ∼0.7 μm dielectric masks to protect the ridge, were implanted with 18O ions. In all cases, the implantation beam flux was maintained at 0.01 μA cm−2. Following 30 s rapid thermal annealing (RTA) in the temperature range 350–750 °C, the sheet resistivities of the InP and InGaAsP samples were determined using either a contactless eddy current or Hall effect measurements. The results show that in both InP and InGaAsP high resistivity layers (∼105 Ω/⧠) are produced by He or O implantation. The thermal stability of the implant-induced isolation depends on the material, the doping type, and the ion dose. High sheet resistivity, stable against 30 s RTA, can be maintained for temperatures up to 550 °C, sufficient for device processing. For samples implanted to calculated (trim) defect concentrations of ∼4×1021 cm−3, p- to n-type conductivity conversion was observed for both InP and InGaAsP.