Single-crystal diamond plate liftoff achieved by ion implantation and subsequent annealing

Abstract

We describe a new method for removing thin, large area sheets of diamond from bulk or homoepitaxial diamond crystals. This method consists of an ion implantation step, followed by a selective etching procedure. High energy (4–5 MeV) implantation of carbon or oxygen ions creates a well-defined layer of damaged diamond that is buried at a controlled depth below the surface. For C implantations, this layer is graphitized by annealing in vacuum, and then etched in either an acid solution, or by heating at 550–600 °C in oxygen. This process successfully lifts off the diamond plate above the graphite layer. For O implantations of a suitable dose (3×1017 cm−2 or greater), the liftoff is achieved by annealing in vacuum or flowing oxygen. In this case, the O required for etching of the graphitic layer is also supplied internally by the implantation. This liftoff method, combined with well-established homoepitaxial growth processes, has considerable potential for the fabrication of large area single crystalline diamond sheets.

Surface damage on diamond membranes fabricated by ion implantation and lift-off

“…When megaelectron volt ion implantation is used, a buried layer of etchable material is created below the surface which can form a sacrificial layer to allow the lift-off of a thin diamond membrane. 7 A wide range of test cavity structures have been fabricated using this method.…”

Diamond Nanophotonics

“…During this process, the lattice damage induced by the stopping of fast ions is used to generate a buried graphite layer that can be etched away to lift of a thin diamond membrane. The original idea was incepted by Parikh in the late 90s [126] , however, only several years ago diamond membranes and basic optical resonators were fabricated [127] . Although rigorous analysis showed that the membranes are made out of pristine, non graphite containing diamond, no optical signature from NV centers was detected and the structures were not optically active.…”

Modification of the structure of diamond with MeV ion implantation

“…This can be achieved by exploiting the strongly non-uniform damage depth profile of MeV ions and creating specific regions where the diamond lattice structure is critically damaged. After annealing, graphitization of the buried layer is achieved whilst the remaining surrounding material is restored to pristine diamond, so that spatially well-defined structures can be created by subsequently etching away the graphitized regions [4] or advantage can be taken from the conductive properties of the graphitized…”