Design of an apertureless two-stage acceleration lens for a single-ion implantation system

Abstract

A single-ion-implantation (SII) system with an implantation accuracy of several tens of nanometers and energy of several tens of kilo-electron volts (keV) is developed to produce an array of nitrogen-vacancy centers (NV centres). The device with the array is expected to be used for quantum information technologies. The system consists of a Paul-trap type laser cooling device (PTLCD) and an electrostatic focusing lens. The PTLCD generates a few single-nitrogen-ions via an ion-cooling procedure. The SII system needs the implantation of single-nitrogen ions with 100% probability, called “deterministic implantation,” to build the array. A focusing lens without an aperture and with a magnification of ≪ 1 must be developed to realize the deterministic implantation. In this study, an electrostatic focusing lens, namely a two-stage acceleration lens, was designed by mainly investigating a second acceleration lens that is suitable for the SII system based on the previously developed two-stage acceleration lens. A new two-stage acceleration lens with a magnification of 0.006 was designed and a numerical simulation based on the lens demonstrated that the beam width for a single-nitrogen ion with an energy of 14 keV was 4.5 nm including intrinsic aberrations at full width at half maximum.