Formation of low energy electron beam with silicon field emitter arrays for space charge compensation in low-energy ion-implantation system

The authors have proposed space charge compensation of a low energy ion beam with silicon field emitter arrays to solve the problem of divergence of low energy ion beam for next generation of ion-implantation system. It is required for the electron sources that they do not contain metal to prevent a wafer from contamination. Therefore, as electron sources, a silicon field emitter arrays treated with trifluoromethane plasma (Si:C-FEA) was adopted. It is required to decelerate the electrons to improve the performance of space charge compensation with Si:C-FEA. However, the electron beam extracted from a Si:C-FEA diverges, and it causes decrease in the current of the electrons during the process of deceleration. In this study, the authors have developed the deceleration electrode system to produce low energy electrons efficiently. Space charge compensation of low energy ion beam was performed to confirm its performance.