Controlling the ion flux on substrates of different geometry by sheath-lens focusing effect

Ion focusing in enhanced glow discharge plasma immersion ion implantation of hydrogen and nitrogen into silicon

“…The ion focusing phenomenon has been investigated by Tian 9,10 a͒ Electronic mail: paul.chu@cityu.edu.hk. and Stamate [11][12][13] and found to be time and space dependent and more severe at a higher voltage and lower plasma density. 9 However, the phenomenon in EGD-PIII has not been studied in details and the effects of the negative bias and plasma density on the ion focusing in EGD-PIII are the objective of this work.…”

Discrete and modal focusing effects: principles and applications

“…So far, based on this phenomenology, a sheath-lens probe for negative ion detection has been developed [26], the ion dose non-uniformity previously reported in plasma immersion ion implantation (PIII) has been correctly explained [27], and solutions to avoid it have been proposed [28][29][30]. Moreover, the possibility of controlling the ion flux to objects of different geometries during ion-induced surface modification has been demonstrated [31].…”

“…An unexpected fact, since the first planar probe was used for plasma diagnostics, was that the charge flux in the saturation regions will exhibit distinctive focusing effects that can be revealed on the probe surface and used to obtain valuable information about the plasma-sheath-surface system. This work shows that three-dimensional plasma-sheath structures exhibit two focusing effects, namely the modal [1] and discrete focusing effects [2] that can be easily visualized on surface both for positive and negative ions and can be used in various applications including plasma diagnostics [3][4][5], ion beam extraction [6], plasma immersion ion implantation [7] and mass spectrometry [8]. It is also demonstrated that one can customize the potential structure within the sheath to realize plasma-sheath-lenses with desired properties regarding the charge flux controllability [5].…”

One-step, non-contact pattern transfer by direct-current plasma immersion ion implantation

“…A one-step, non-contact pattern transferring method based on long-pulse plasma immersion ion implantation (PIII) has been recently proposed [1]. Ions can be focused by the plasma sheath but specific patterns are hard to transfer since the ion sheath is dynamic [2,3]. In this method, specific images with well-defined boundaries are simultaneously transferred to a substrate by PIII through a patterned metal mask.…”

“…In this work, the potential application of this method is demonstrated by experimentally transferring patterns with micrometre linewidths to a silicon wafer and corroborated by theoretical simulation. 3 Authors to whom any correspondence should be addressed.…”