Ion-matrix sheath structure around cathodes of complex shape

Abstract

Numerical methods have been used to find the electric potential distribution in the stationary ion sheath that initially surrounds wedge-shaped cathodes in a plasma, following the application of a large negative voltage pulse.

Investigation of the ion dose non-uniformity caused by sheath-lens focusing effect on silicon wafers

“…1. H 2 plasma density, ranging from 7 × 10 14 m − 3 up to 7 × 10 16 m − 3 , was monitored by a plasma absorption probe (PAP) connected to a high speed Network Analyzer [10]. Silicon wafers of 100 mm in diameter have been biased from − 5 kV down to − 10 kV at a fixed pulse width of 50 μs, and a pulse frequency of 20 Hz.…”

“…As a result, the sheath is a two or three dimensional structure in which potential distribution determines the ion motion until reaching the surface. Over the years, significant efforts were devoted to predict and improve the ion flux over the treated surface [9][10][11][12].…”

Theoretical Study on Dose Distributions of the Ball Bearing Treated by Plasma Immersion Ion Implantation

“…where D = 4ε 0 |φ p |/qn 0 is the ion-matrix overlap length [8], ω pi = n 0 q 2 /ε 0 M is the ion plasma frequency, and V max = 2q|φ p |/M is the ion velocity corresponding to a potential drop φ p , where φ p is the applied target potential. The normalized formulas are then…”

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

“…One emerging technology is plasma immersion ion implantation (PIII) where objects of complex geometry are bombarded with high energy ions accelerated in a time dependent sheath created by applying a pulsed bias of the order of tens of kV [9]. Non-uniform treatment (ion dose) associated with targets of different geometry have been reported in the last two decays [10][11][12][13][14][15] and elaborate simulations and experiments have been done to estimate the ion flux impinging on the surface [16][17][18][19][20][21][22][23][24][25]. Following our interest in charge focusing by two or three-dimensional plasma-sheath systems we demonstrated that PS formation reveals useful information about D sh [26], and that the negative ion focusing can be used as a diagnostic technique for electronegative plasmas [27].…”