Highly Efficient Small Anode Ion Source

Vadim Dudnikov,Andrei Dudnikov

doi:10.3390/plasma4020013

Abstract

We describe some modifications to a Bernas-type ion source that improve the ion beam production efficiency and source operating lifetime. The ionization efficiency of a Bernas type ion source has been improved by using a small anode that is a thin rod, oriented along the magnetic field. The transverse electric field of the small anode causes the plasma to drift in the crossed ExB field to the emission slit. The cathode material recycling was optimized to increase the operating lifetime, and the wall potential optimized to suppress deposition of material and subsequent flake formation. A three-electrode extraction system was optimized for low energy ion beam production and efficient space charge neutralization. An ion beam with emission current density up to 60 mA/cm2 has been extracted from the modified source running on BF3 gas. Space charge neutralization of positive ion beams was improved by injecting electronegative gases.

Highlights

A review of ion source development for ion implantation and isotope separation has been well described elsewhere [1]
The Bernas–White ion source (BWIS) is the most widely used in high current ion implanters [1], and several versions of BWIS are manufactured by some industrial companies [2]
We have developed and tested a modification to the widely used Bernas-type ion source that has a number of significant advantages

Summary

Introduction

A review of ion source development for ion implantation and isotope separation has been well described elsewhere [1]. The Bernas–White ion source (BWIS) is the most widely used in high current ion implanters [1], and several versions of BWIS are manufactured by some industrial companies [2]. Somewhat more complicated versions of BWIS with two filaments or indirectly heated cathodes have been used for high current and multicharged ion beam production [3,4]. Further improvements of the ion beam parameters and increased ion source lifetime are necessary for advanced ion implanters. We describe some modifications to a Bernas-type ion source that improve the ion beam production efficiency and source operating lifetime.

Small Anode Ion Source

With injectionelectronegative of the electronegative gases

Findings

Conclusions