y. miyagawa (aist)ccp2006 gyengju plasma analysis for piii processing by a pic-mcc simulation y....

Y. Miyagawa (AIST) CCP2006 Gyengju

Plasma analysis for PIII processing by a PIC-MCC simulation

Y. Miyagawa, M. Ikeyama, S. Miyagawa National Institute of Advanced Industrial Science and Technology

(AIST Chubu-center), Nagoya, Japan

M. Tanaka, H. Nakadate PEGASUS Software Inc., Tokyo, Japan

Outline1. Introduction ( about PIII and PEGASUS )2. Plasma around a trench shaped target. 3a. Hollow cathode discharge Plasma in a pipe.3b. Plasma with a grounded rod on the center of a pipe.4. Gas flow and Plasma inside of a PET bottle.5. Plasma around plural targets6. Summary


The development and applications of plasma processing such as plasma assisted CVD and PVD, magnetron sputter processing, plasma immersion ion implantation (PIII), etc. become highly important in various industrial fields. In plasma processing, plasma control is the topmost priority.

In PIII, the complex sheath shape which is formed around a complex shaped target affects strongly the energy and the flux of the implanted ions on the target surface, and so, affects the compositional depth profile of the treated surface and the homogeneity and the adhesion strength of the coatings. In order to analyze the plasma and to find the most appropriate condition for the process, computer simulation is quite useful.

Introduction


In order to analyze the behavior of charged particles and neutral atoms in the plasma together with the gas flow, the simulation software "PEGASUS” was developed. For low pressure gas system, PIC-MCC (Particle-in Cell + Monte Carlo Collision) methods are used.

Using PEGASUS, 4 types of simulation were performed.

ＰＥＧＡＳＵＳ（ Plasma Enhanced materials processing and

rarefied GAS dynamics Unified Simulation tools ）


A : with a Cartesian coordinate system gas:ArPlasma around a trench shaped target immersed in a high density Ar plasma. A negative pulse voltage was applied to the target.

C : with a cylindrical coordinate system gas:Ar, N2

For inner coating of a PET bottle; Glow discharge plasma with a thin pipe on the center. Gas is injected from the tip of the pipe.At first, the gas flow field was simulated by DSMCM until it reached the steady state. Then, coupling simulation of the DSMCM and PIC-MCCM was performed.

B : with a cylindrical coordinate system gas:ArFor inner coating of a pipe; Hollow cathode discharge plasma Glow discharge plasma with a grounded rod on the center.

D: with a cylindrical coordinate system gas:N2, ,C2H2

For processing of plural targets; Glow discharge plasma generated by a negative pulse voltage after a positive- or a negative- pulse voltage were simulated and compared.


Simulation Scheme of Gas Phase Simulator

PHM PIC-MCCM

Plasma

Static Electric FieldIon-Electron DensityIon-Electron FluxEEDF

NMEM DSMCM

Gas DensityRadical DensityRadical Flux

Gas FlowData Base

GUIM

input data

Output monitoring final results

MODULES Coordinate system : Cartesian and cylindrical

PHM (Plasma Hybrid Module) (high density gas)NMEM(Neutral Momentum Equation Module) (Fluid Model: high density gas)PIC-MCCM(Particle-in-Cell-Monte Carlo Collision Module) (low density gas)DSMCM(Direct Simulation Monte Carlo Module) (Particle Model: low density gas)GUIM (Pre/Post Processor)

PIII is processed in a low density gas (0.1 ～ 100 Pa)


In the PIC method, movements of super particles ( a bunch of charged particles of the same kind ) are followed. The charge and the mass of a super particle are from 108 to 101

0 times the real particle depending on the statistical condition.

DSMCM is based on a probabilistic method for solving Bolzmann equation. By using the super particle Monte Carlo method, the gas flow field is rapidly calculated for the case that the density of neutrals such as radicals or sputtered particles is very low in comparison with the fed gas atom density.

The collision rates are calculated based on the energy dependent cross section.

Simulation Method

Y. Miyagawa (AIST) CCP2006 Gyengju Y. Miyagawa (AIST) IUMRS-ICAM-2003 Yokohama

Energy dependence of Collision cross sections of an electron with an ion

σtot =σm+σdi+σsi+σex

σm : momentum transfer e + Ar Ar + eσdi : direct ionization e + Ar Ar+ + e + eσsi : secondary ionization e + Ar* Ar+ + e + eσex : excitation e + Ar Ar* + e

Momentum transferM. Hayashi, Institute of Plasma Physics Report No. IPPJ-AM-19, (1981)direct ionizationD. Rapp and P. Englander-Golden, J. Chem. Phys. 43, 1464 (1965)secondary ionizationY. Nakamura et al, 1989 Technical Paper of Electrical Discharge, IEE, ED-89-72excitationA. Chutjian and D.C. Cartwright, Phys. Rev. A23, 2178-2193 (1981)

10-14

10-15

10-16

10-17

10-18

10-19

cros

s se

ctio

n (

cm2)

1 10 1000.1

electron energy (eV)

σm σdi

σex

σsi

Example of database : Ar gas


Ion Source

Target Beam Scanner

Ion BeamAnalyzing Magnet

Pumping

Ion Beam Implantation using an Accelerator

Plasma Immersed Ion Implantation (PBII, PIII)

Plasma Source

PumpingHigh Voltage Pulser

+

-

Target

Difficult to implant to a large area or a complicated shaped target

For a large area or a complicated shape target.Simple system structure is another good point.But,Not easy to process the target with a narrow hole, trench, etc, or inside of a pipe.Non single ion implantation is another demerit


Plasma Immersed Ion Implantation

When a pulsed negative high voltage (V) is applied to the target which is immersed in a plasma, an ion sheath is formed around the target.

The potential of the plasma is about a few ten voltage, so, ions are implanted from the sheath edge to the target.

パルス波形

Time (micro sec)

volta

ge (

V) -100-200-300-400-500

0

0 2 4 6 8 10

Plasma

ion

target


Cartesian coordinate system gas:Ar

PIII condition;

Plasma around a trench shaped target immersed in a high density Ar plasma. A negative pulse voltage was applied to the target.

Simulation A


Time (micro sec)

volt

age

(V) -100

-200

-300

-400

-500

0

0 2 4 6 8 10

Results of simulation : Trench shaped target Ar plasma （ 0.1 mTorr, 1016 m-3 ) Vmax : -500V = 1

Pulse shape

1cm 1cm

2cm

distance (cm) distance (cm)

dis

tan

ced

ista

nce

dis

tan

ce (

cm)

2 41 30 2 41 30

2

1

0

2

1

0

2

1

0

3

10.8 s

8.4 s

7.2 s 1.2 s

2.4 s

3.6 s

Time evolution of plasma density near the target

　 0

1016

(m-3 )

Blue area is the ion sheath where electrons are repelled out.Red area is filled with high density plasma.


0

10

20

30

0 2 4 6 8 10Time (s)

Ion

Flu

x (a

.u.)

simulation analytical

-2 kV

-5 kV

Vmax = -20 kV

Sh

eath

Len

gth

(cm

)

0

1

2

3

4

5

0 2 4 6 8 10Time (s)

-2 kV

-5 kV

-20 kV

Ar ( 1016 m-3 )

Sheath length on the flat part of the target surface.

Comparison of the simulation results with the analytical results based on the Child-Langmuir method. 　　Initial Ar plasma density = 1x1016 m-3

Analytical solutions are only for a planer, cylindrical and spherical targets.No solutions for a complicated shape target.

Ion flux on the flat part of the target surface.


Position dependence of the ion flux on the surface of the trench shaped target.

0.5

1.52.3510

s

bottomside

outside

top

ion

flu

x (1

015 c

m-2 s

-1)

0

1

2

3

4

5

6 -2 kV

sbottom

side

outside

top

0.51.52.356100

2

4

6

8

10

0 13 26 39mmPosition

(distance from the center)io

n f

lux

(1015

cm

-2 s

-1) -20 kV

13mm

13m

m

2mm

bottom

sid

e

ou

tsid

e

top

Ar :1 mTorr, 1x1016 m-3

Time increases short

sheath length increases short

ion flux decreases(bottom, top) high(inside) medium

long

long

lowlow

When V is high, Ion flux is high, sinceself ignition plasma generates.

Ion flux to the inside surface is very low, especially for V is high.

When plasma intensity is high, sheath length is short.For conformal implantation, high plasma intensity is desirable.

Y. Miyagawa (AIST) CCP2006 Gyengju Y. Miyagawa

with a cylindrical coordinate system gas:Ar

For inner coating of a pipe.Hollow cathode discharge plasma was simulated.

Glow discharge plasma with a grounded rod on the center was also simulated

Simulation B


Simulation of Hollow Cathode Discharge

When a negative voltage is applied to a cylindrical target, a high density plasma is generated inside of the target as a result of hollow cathode discharge effect under a special condition. The hollow cathode discharge plasma can be applied to inner coating of a cylindrical target.

In order to obtain the condition for a hollow cathode discharge, PIC-MCCM simulation was carried out.


Comparison of Plasma Intensity

Glow discharge Hollow Cathode discharge

The hollow cathode discharge plasma is several order more intense than the glow discharge plasma.


Schematics of the model10cm, 10mm

20cm

, 20m

m

Ar

r = 1cm, 2cm, 2mm

l = 5, 10, 15, 30 cm (mm)

dr = 1 mm, 0.1mmr

l

z

20 cm

r

-V

l

Plane anode

Cylindrical target (cathode)

cm-size 　 & 　 mm-size without a rod & with a rod

A quarter (pink area) was simulated with a cylindrical coordinate systemGrounded rod

Y. Miyagawa (AIST) CCP2006 GyengjuAr 50Pa DC -3kV

l = 5 cm, radius = 2 cmaspect ratio ( l / r ) = 2.5

At 1.2s, an intense plasma fill the whole inside of the pipePendulum motion occurs

1012

(m-3 ) 1017

0.2 s 0.4 s 1.0 s 1.2 s

electron flux on the wall

Ar ion density

electron density

1

40eV

electron temperature

Ar+ ion temperature

max=105

0.2 s 0.4 s 1.0 s 1.2 s

electron flux

0.1s

10cm

5cm

r =2cm

20c

m

Y. Miyagawa (AIST) CCP2006 GyengjuAr 50Pa DC -3kV, = 1

l = 5 cm, radius = 2 cmaspect ratio ( l / r ) = 2.5

When a negative high voltage is applied to the pipe,Electrons start to move towards the anode, collide with gas atoms and plasma generates near the exit of the pipe.

The plasma enters the pipe.

Finally at 1.2s, pendulum motion occurs, and

intense plasma fill the whole inside of the pipe

0.2 s 0.4 s 1.0 s 1.2 s

Ar+ ion temperatureelectron flux on the wall

electron density

electron flux

0.1 s

Y. Miyagawa (AIST) CCP2006 Gyengju Electron density just before the discharge Voltage : pulse ( Vmax = 1kV)

20cm

10cm

5cm

Gas Pressure Dependence

1 Pa 3 Pa 10 Pa 30 Pa 100 Pa 300 Pa

1012

1017(m-3 )

r = 1cm, 1000 V = 1

Discharge outside

Pressure is too low

Glow discharge? plasma

Pressure is too high

Hollow cathode plasma

Proper condition


radius = 2 cm, half length = 5 cm

Applied voltage Dependence Gas pressure ： 2Pa = 1

Low VoltageNo Plasma

1012

1014

(m-3 )

30 V1012

1017

(m-3 )

1000 V

High VoltageDischarge outside

Proper voltageHollow Cathode Discharge Plasma

1012

1017

(m-3 )

100 V

Y. Miyagawa (AIST) CCP2006 GyengjuEffect of secondary electron emission coefficient by ion bombardment)

Ar gas, pulse rising time : 0.5s, radius = 2cm ( d = 4cm)

Pmin strongly depends on

=1: plasma generates for pressure > 1Pa

= 1, Vmax= 200V

1012

1017(m-3 )

2Pa 10Pa

= 0.3, Vmax= 200 V

6 Pa 20 Pa 60 Pa 2 Pa

20c

m

10cm1012

1017(m-3 )

=0.3 ： for pressure > 4Pa

= 0.1

2Pa-1kV 6Pa-200V 6Pa-1kV 2Pa-200V

1012

1016(m-3 )

=0.1 ： no hollow cathode plasma


Pressure x diameter (Torr.m)

Ap

plie

d v

olta

ge

(V

)

10-2 10010-110-310-4

102

103

104

101

Paschen curve (Ar gas )

= 1

cm -sized

Paschen CurveA glow discharge starts with the voltage higher than the curve.

Summary for a pipe of small aspect ratio ( < 7 　 )

● ○ 　 Hollow cathode plasma generates. ★ ☆ Glow discharge starts outside the pipe.

▲ △ High density plasma does not generates.

Dischargeoutside(cm)

Hollow cathode discharge

mm-sized

Discharge outside (mm)

No plasma generates

The hollow cathode discharge condition is much sever for a mm-sized pipe than a cm-sized pipe.


10-4 10-3 10-2 10-1

0

-5

-15

-10

-20

PRESSURE(Torr)

VO

LT

AG

E(k

V)

Diameter: 30mm10 mm

Ar

Hollow Cathode Discharge

Hollow Cathode Discharge Condition

experiment

The smaller the size is, the condition becomes severe.


Example of pipe inner coating

1cm 4cm


for a pipe of higher aspect ratio

1012

1017(m-3 )

50Pa, DC - 3 kV = 1 radius = 2 cm

l = 5 cm l = 10 cm

Plasma spreads whole inside the pipe

l = 15 cm

Plasma does not reach the middle


1012

1017(m-3 )

Long pipe with a large aspect ratio ( d/L > 7 )

Without a rod

50PaDC - 3kV

radius : 2 cmlength : 30 cm

d

L

Hollow cathode plasma.

A glow discharge plasma fills the whole inside. 　 How long the pipe is, it works.

1kPaRF-500V

300PaDC-500V

radius : 2 mm,length : 30 mm

Not only for the cm-sized pipe, it also works for a mm-sized pipe.

Plasma in the middle part is insufficient.

With a grounded rod on the center

100PaDC - 1kV

300PaRF -1kV

radius : 2 cm,length : 30 cm


Glow discharge inside of a pipe with a ground rod on the center

(-3kV, 10sec, 1kHz)

3 cm

The glow discharge plasma needs much higher pressure than for a hollow cathode discharge

Ar:100 Pa Ar: 5 Pa


Long pipe with high aspect ratio ( d/L > 7 )

300Pa, Vmax= 500V

diameter : 4 mm, 　 length: 30 mm

Simulation (Ar) Experiment (CH4)

1012

1017

(m-3 )

diameter : 2.2 mm, 　 length : 50 mm

0.15 mm0.2 mm

380Pa, Vmax = 　 500V

Grounded rod on the center

3 mm


Example of DLC coating on inside surface of a pipe

length 　50mm

Inside diameter 　 1.6 mm 4.5 mm

Non

coa

ted

Diameter 　 1.6 mmCH4 1000PaVmax 500VPulse length 　 10sFrequency 　　　 1kHzdiameter 　 4.5 mmCH4 300PaVmax 500VPulse length 　 10sFrequency 　　　 1kHz

coat

ed

Y. Miyagawa (AIST) CCP2006 Gyengju Y. Miyagawa

with a cylindrical coordinate system (Ar, N2 )

For inner coating of a PET bottle;

Glow discharge plasma with a thin pipe on the center. Gas is fed from the tip of the pipe.

Simulation C


In recent years, the inner coating of a PET ( polyethylene terephthalate ) bottle with DLC gathered much interest. It drastically decreases the permeability of oxygen and other gases. It will make a PET bottle a superior substitute for a heavy glass bottle. PIII is suitable process for such inner coatings of DLC. However, in JAPAN, so far, beer breweries withhold it in consideration of the reaction of green organizations, regardless the effect of the coating on the recycling is negligible.

environmental conservation


Inner coating of a PET bottle:

Gas is injected into the bottle. So,Simulation of gas flow (MCC) and plasma (PIC+MCC) was carried out alternately.

Before starting plasma simulation, the gas flow was analyzed using Monte Carlo collision method.After the pressure reached the steady state, the plasma simulation by PIC-MCC started.


Cross sections of collisions in N2 plasma

10 100 1000

energy (eV)

10-17

10-16

cros

s se

ctio

n (c

m2)

e + N2 --> 2e + N2+

e + N2 --> 2e + N2*

e + N2 --> e + 2N

e + N --> 2e + N+

ionization

excitation

resolution

ionization


The N2 gas pressure distribution obtained by DSMCM after it reached the steady state.

8 7 6 5 4

11

10

2

19

3

distance (mm)0 10 20 30

pre

ssu

re (

Pa)

pressure at H = 50 mm

1210

86420

0

20 Pa

N2

5 sccm

gas inlet

pipe ( radius 3mm): +V is applied

PET bottlecover: grounded electrode

0 10 20 30 mm0

15

50

74

115

145

170

insulator

insulatormm

time (s)

250

0

500

0 1 2 3 4 5 6 7 8

applied voltage

volt

age

(V)


3.5e15

0

Evolution of electron density

Ar 5 Pa Vmax = 500V 10 s

Results of the simulation

time (s)

250

0

500

0 2 4 6 8 10 12 14 16

applied voltage

volt

age

(V)

s0.1 2 4 6 8 10 11

Plasma density increases even after the voltage is off.


Time evolution of densities of electron, N2+ ion, N atom,and N2* radical.

1013

m-3

3x1018

1 2 3 4 5 8 s

1013

m-3

1016

e

1013

m-3

1016

N2+

1 2 3 4 5 8 s

1013

m-3

3x1017

N

N2*

N2 10 Pa500V, 5 s = 1.

Plasma shape depends on the gas species, the pressure, the voltage, , the gas feeding speed, etc..


N2 10Pa, 500V, 5 s,= 1

Plasma intensity increases even after the voltage was off, but

Time ( micro sec )

9

8

765

11

0

1

2

x1016

Den

sity

(m

-3)

incr

ease

9

876

5

11

0 82 4 6

Den

sity

(m

-3)

x1016

0

1

2

incr

ease

Vo

ltag

e

　

(V)250

0

500

electron

N2+

Applied Voltage

Ion flux and Ion energy flux at 5 s ( V = 500 V ) and at 8 s ( V = 0 )

Energy Flux

123123 3.3 1.2

Particle Flux

Max intensity ( x1019 )

8 s5 sdecrease

Max intensity ( x1019 )

8 s5 sdecrease

the particle flux on the inside wall decreases

Y. Miyagawa (AIST) CCP2006 GyengjuDensity at each observation point. N2 10 Pa, 500V, 5s, = 0.5

8 7 6 5 4

11

10

2

19

3

den

sity

(10

15m

-3) 6

4

2

0

electron7

8

11

5

6

4

N2+ ion

5

6

8

11

7

4

4

2

0

den

sity

(10

15m

-3)

den

sity

(10

16 m

-3)

4

2

0

N2*radical

0 25 50 75Time ( s )

Comparison with exp.

Time ( s)0 500 1000 1500

Ion

den

sity

(10

16m

-3)

Ar 2Pa1kV, 5s

experiment

Time after V was off ( s)

CalculationN2 10Pa

0

1

2

3

4

5

Regardless of the difference of gas species,

Similar result was obtained !!!

After the voltage was off,the plasma intensity increases, and reaches the maximum at ~2s, then decreases slowly.


Comparison of the calculated result with an experiment

The grounded cover was removed to take the photo.

Ar gas pressure; outside: about 2 Pa, inside : unknown 1kV, 5 s, 0.5 kHz.

experiment simulation.

Ar gas pressure: about 10 Pa. 500V, 5 s


0

1000

2000

3000

4000

800 1000 1200 1400 1600 1800 2000

Raman spectrum

Example of DLC coating inside of a PET bottle

C2H2 gas pressure: outside: about 2 Pa, inside: unknown 1kV; 5s, 1 kHz.

Typical DLC spectrum


with the cylindrical coordinate system Gas:N2 and C2H2

For processing of plural targets

Simulation D


In the PIII processes, negative pulse voltages are applied to a processed target, and the ions are accelerated in the sheath and implanted on the target surface.

So, for practical applications, especially for processing plural targets simultaneously, it is very important to know the plasma behavior in the surroundings of the targets.

One of our purposes is to find the optimal conditions for DLC coatings on a complex shaped target and on plural targets.

We have performed simulations for the N2 and C2H2 plasma behavior in the surrounding of plural targets, to which three types of negative pulse voltage were applied:

case A: a single negative voltage, case B: a negative voltage then a negative voltage (double negative)case C: a positive voltage then a negative voltage ( bipolar )

An N2 gas plasma have been used in PIII processing to modify the surface mechanical characteristics by nitriding or carbonizing the surface.


Schematics of the simulated system.

200 mm

250

mm

50 mm

19 mm2 mm

38 mm

38 mm

38 mm

Pulse shape

Time (s)0 5 10 15 20

1

0

-1V

olt

age

(kV

)

Target 1

Target 2

Target 3

Target 4

The y axis is the symmetric axis of the cylindrical coordinate system.

The x-axis is also symmetric.

Chamber wall is grounded.


25

20

15

10

5

0

25

20

15

10

5

0

6 s4 s2 s

8 s7.5 s 7 s

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

1012

( m-3) 2 x1015

+1k

0

-1k0 5 10 15 s

A: single negative V

-1kV ( 0 ~7 s ) 2Pa, = 3

plasma is too weakX


1012

( m-3) 2 x1015

25

20

15

10

5

0

25

20

15

10

5

0

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

6 s5 s2 s

16.5 s15s10 s

B: Negative and negative

-1kV (0~5 s) then -1kV(10 s ~) 2Pa, = 3

Discharge starts !!unstablex

+1k

0

-1k0 5 10 15 s


1012

( m-3) 2 x1015

25

20

15

10

5

0

25

20

15

10

5

0

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

12.2 s12 s10 s

6 s5 s2 s

Plasma is between targets

+1k

0

-1k0 5 10 15 s

B: Positive then negative

+1kV (0~5 s) then -1kV(10 s ~) 2Pa, = 3


25

20

15

10

5

0

25

20

15

10

5

0

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

0 5 10 15 20 0 5 10 15 20 0 5 10 15 20

6 s5 s1 s

15 s11 s10 s

no plasmabetween targets !!x

Low : = 2

+1k

0

-1k0 5 10 15 s

C: Positive then negative

+1kV (0~5 s) then -1kV(10 s ~) 2Pa, = 2same pressure, only is low

1012

( m-3) 2 x1015


Effects of gas pressure and the secondary electron emission coefficient ()

The pressure and the is high

The plasma generation rate is high.

The sheath length is short anda conformal implantation is realized 1012

( m-3) 2 x1015

25

20

15

10

5

015 s15 s

12.2 s

0 5 10 15 20 0 5 10 15 20

0 5 10 15 20

1.5Pa

= 3

2Pa

= 3

2Pa

= 2

25

20

15

10

5

011.5 s

0 5 10 15 20

3Pa = 2

X X

+1k

0

-1k0 5 10 15 s


+1kV (0~5 s) then -1kV(10 s ~)


0

200

400

600

800

0 5 10 15Time ( s )

Ion

En

erg

y (e

V) Time dependence of

Ion energy on the under surface of target 3 0 cm

3 cm

5 cm

distance from

the center

Vo

ltag

e (V

)

-1000

0

1000 Pulse shape

+V on : plasma generates

V off : plasma migrate between targets

-V on : sheath is formed ions impinge on the target surface

Ion energy along the target surface.

11.5s0

200

400

800

400

600

800

1000target 1target 2

0 1 2 3 4 5

En

erg

y (

eV)

En

erg

y (

eV)

Distance from the center axis (cm)

upper surfaceunder surface

target 3target 4

0

200

400

600

800

1000

25

20

15

10

5

011.5 s

0 5 10 15 20cm

3Pa = 2

Vmax = 1 kV

Max ion energy reaches 1 keV


+1kV (0~5 s) then -1kV(10 s ~)

4321


Time dependence of number of super particles ( 1 kV, 5 s). C2H2, 3Pa, = E depend ( 1 at 1 keV)

H ( 22.0 )CH ( 9.3 )C2H ( 9.0 ) CH2 ( 4.9 )

C2H2+ (19.0 )

C2H+ ( 2.9 ) CH+ ( 1.2 ) H+ ( 1.0)C2H2

2+ ( 0.6 )

Density near the sheath edge at 5 s x 1013 m-3

3 Pa C2H2 ( 7.17x1020 m-3 　 )

Total number of super particle was set to 106, so, the curves are saw-like.

Most abundant ion is C2H2+

Most abundant atom is H

0 2.5 5.0 7.5 10

Time ( s )

num

ber

of p

artic

les

num

ber

of p

artic

les

106

105

104

106

105

104

103

H

CH

CH2

C2H

eC2H2

+

C2H+

CH+

H+C2H2

2+


The nitrogen and the acetylene plasma around plural numbers of targets has been simulated under the condition of PIII.

The self ignition plasma generated by the first pulse migrates to the space between targets during the voltage off time and it gets denser when the second pulse is on and the plasma becomes conformal to the targets when the density gets intense enough. It depends on the pressure and the secondary electron emission coefficient if the plasma becomes conformal or not before the discharge starts. .

The bombarding ion energy on the target surface and its time dependence was also presented. .

For C2H2 gas plasma, the time dependence of densities of ions ( e, H+, CH+, C2H2

+, C2H+, C2H22+) and molecules ( H, CH2, CH, C2H))

generated by a positive pulse voltage was also presented. .


Plasma analysis for PIII&D processing by a PIC-MC simulation

Outline1. Introduction ( about PIII and PEGASUS )2. Plasma around a trench shaped target. 3a. Hollow cathode discharge Plasma in a pipe.3b. Plasma with a grounded rod on the center of a pipe.4. Gas flow and Plasma inside of a PET bottle.5. Plasma around plural targets6. Summary

Thank you for your attention

Y. Miyagawa (AIST) CCP2006 Gyengju 10-14

10-15

10-16

10-17

10-18

1 10 100 1000ENERGY ( eV )

CR

OS

S S

EC

TIO

N (

cm

2 )

e + N2 -> 2e + N2+

e + N2 -> e + N2

e + N2 -> 2e + N2*rot

e + N2 -> e + 2N

N2+ + N2 -> N2

+ + N2

N2+ + N2 -> N2 + N2

+

e + N -> 2e + N+

e + N -> e + N

e + e -> e + e

Energy dependence of cross sections for collisions in a plasma.

C2++ H2 + 2e

C2H22+

+2e

C2H+ + H + 2e

C++ CH2 + 2eCH++ CH + 2eH++ C2H + 2e

C2H2+

+ 2e

e + C2H2

10-15

10-16

10-17

10-18

10-19

10 100 1000 10000ENERGY ( eV )

CR

OS

S S

EC

TIO

N (

cm

2 )

N2 plasma.

C2H2 plasma.

y. miyagawa (aist)ccp2006 gyengju plasma analysis for piii processing by a pic-mcc simulation y....

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