The effects of ion implantation on optical spectra of SiO2 glass

Journal of NonGyrtalline Solids 95 & 96 (1987) North-I-lolland. Amsterdam

THE EFFECTS SPECTRA OF J.D.

OF SiOp

Stark,

*Oak Oak

Weeks,

National TN

ON

G.

h Materials University, Ridge Ridge,

685

ION IMPLANTATION GLASS

R.A.

Mechanical Vanderbilt

685 - 692

OPTICAL

Whichard.

D.L.

Eng. Dept. Nashville,

TN

Kinser,

h

R.

A.

Zuhr*

37235

Laboratory 37831

Optical absorption of ion implanted amorphous SiO2 "as measured in the energy region 1.0 to 6.5 eV. Both sides of silica wafers (Spectrosil and t,, sdb”,‘,~oosfi~xlwoF1)6, ~‘;,‘,,:~p’“:~~“,,;~~~ either ;r', Mn+ or Fe+ ions/cm per side at 160 keV and 4 pA/cm Distributions of the implanted species were determined by ion backscattering techniques and, within experimental error, were the same for all doses and species. For each ion specie the spectra, when plotted as extinction coefficient increased ion, with Per increasing dose throughout the entire range of measurement. The intensities of the optical absorption spectra were a function of ion specie. There "as no evidence for effects of substrate type in the absorption spectra. Evidence for three previously reported bands associated with irradiation damage spectra. These bands are: effects "as observed in all optical the B2 band (5.05 eV), the El' band (5.8 eV), and the low Assuming a Gaussian energy tail of a band centered at 7.15 eV. shape for the B2 and El' bands and a Lorentzian shape for the band at 7.15 eV and constraining the peak energies and full widths at half maximum amplitude (FWHM) to previously reported values, the observed data were fitted when two additional bands were included in the fitting. These are the D, and E2' bands respectively, which were similarly conat 4.8 and 5.31 eV. strained. Optical absorption due to the implanted species has these ions is not been detected. The chemical state of tentatively assumed to be a mixture of the chemical state of and higher states. the ions preceding implantation, i.e. +1. interactions e.g. +2 and +3, which are a consequence of the implanted ion and the substrate. The effect of between the these states on the optical absorption will be discussed. 1.

INTRODUCTION Ion

implantation

is

important

applications

finding fabrications used of

and to

si

metals

siderable

I

optical

waveguides

optical

properties

semiconductors

producing

grating

0022-3093/87/$03.50 (North-Holland

Physics

has in by couplers

0 Elsevier Publishing

processing electronics,

technologies. modify

improvement

materials in

coating

nificantly ,

a

2

3 implantation

surface and

been

LiNbO

Ion

the

for

Science Publishers Division)

that

optical

waveguide

implantation

and

n;ar

Ti

on

the

Recently,

optical

B.V.

waveguides.

be;"

been con-

of Alterations

also

is

regions

fabrication

implantation have

has surface

insulators

made by

technique

utilized

planar of in

686

J. D. Stork

Silica shock

glass

has

resistance.

range

of

low

many

optical of

disordered

structure

ions

from

in

silica.

in

SiO

first

for 0 ,7 glass

2

Fe+), ions/cm

t2he

Thus

it

provides

an

can

be

measured

without

per

dose

v-SiO

introduction

Here

we

report

the

a function

side),

of

and

optical

implantation

type

of

proves

to

magnetic of

,

t 11e

to

be

effects implantation

specif6(Cr+.

(1x10

substrate

Also, due

effects \;n

in

impurities.

and

optical

ions

material interference

elements

implanted

implanted

Of

of

of

ideal

The

series

wide

extremely

minimized

substrate.

transition

the as

the

are

thermal

very

with

and

ions

es a

available

ions

implanted2

of

the

interestin

also

implanted

the

such over

is

between of

glttm

transparency

It

effects

effects

of SiO,

properties

and

impurities.

interactions

ordering

sprctrtt

desirable

wavelength.

implantation

from

Optical

elasticity

levels

which

PI al. /

tin+

3x10

,

(Spectrosil

and

or

%

6x10

Spectrosil

WF). 2.

EXPERIMENTAL 2.0

cm

Spectrosil

WF)

series

of

doses

,

1x10 200-1000

przfjles These

Cary

reference

beam.

absorption implantation

the

form I

3.

implantations.

by

a

and transision

and

4

side Per Implantation

pA/cm

to

using

an depth

techniques

Van

de

at

the

1.0

to

and

absorption

Graaf

Solid

spectrophotometer

made

in

reflection

using

accelerator.

State

losses SiO

Thus,

the

to

Division

of

each

using

a basic

c

least

are

to of

X2

the

SiO in

the

caused

2

by

presented

in

vs

absorption

energy

per

experimenta:

analysis

To

the difference

(l/ion/cm),

spectrum fits

the damage

obtained

coefficient,

to

placed

was the

all

range.

due

and

spectra

for

energy

was

ions

simulated

utilized

eV

measured

implanted The

6.5

substrate

2

absorption

the

was

the

unimplanted

EXPERIMENTAL Figure

MIl+

beam

Computer

generated

backscattering

out

normalizing

ion.

1602keV

MeV

carried

extinction

thereby

planted

first

ions/cm

ion 2

process. of

at

6x10

by

dual

due

the

or

(Spectrosil

the

Laboratory.

14

an

wafers from

accelerator.

to

measurements for

silica ions + Ff6)

implantation

were

substrate,

were

with

National

compensate

(eV)

thick

determined

procedures

optical

0.1

accelerated

Ridge A

cm

implanted + (Cr "tl+, 16' 3x10 , and ion

were ions

He

in

x were

elemle6nts

of

Extrion

Oak

PROCEDURE diameter

im-

spectra

program

RESULTS 1

shows

the

depth

The

profiles

profiles

of are

Gaussian

three

differett in

shape

doses with

of peak

concentration

Eace

at

and

profiles

are

which

the

1.

Depth

As 6.5

eV,

to

2.5

eV

from

to

Fi

2

6.5

at

an

for

each

eV

It

can

sents process

a

is

due per in

Figure

the

the

to side

order

This

Mn

can

Cr

<

seen

is

same

and

Arnold

, tail

eV

also

that

due

feature 3

a dose

in

absorption all

the

repre-

implantation

Figure to

to

spectra the

was

was

Another

to

for

feaarTothe

E ' band which 1 a low energy

ion. in

vs

different These

each

increase the

1.0

(l/ion/cm)

absorption

since

implanted The

Fe

and

due be

,

al

implanted

species

compared. <

the

dose

1.0

the spectra

resolvable

7.15

absorption

ion

are

that

from in

The

the ,

at

per

optical

three

Nelson

2

made

three

et tl;

of

absorption

that

Antonini,

function

ion-specific.

absorption ions/cm

from

linear

were

bants.

attributed

9

al

v-SiO2.

the

ions.

absorption

and

into

c of

three

centered

FWHM.

absorption

coefficient, the

surThese

implantations

detected

optical

samples

Weeks

et

optical is

eV

band

seen

not

the note

by

Antonini be

is

the

by

5.8

were

the

case.

+

Fe

implanted

shows

from

and

bands

three

reported

at

by

damage

of are

and

measurements

extinction

absorption

reported

optical

spectra

5.05

ions

implanted

observed

from

sity

as

+

Cr

pm each

in

concentration

Mn

2

pm

the

absorption

ion

inflection

originally

to

eV

these

band

minor

all

for

peak

of

Figure

doses of

of

no

range.

implanted tures

depth

above,

0.11

0.14

of

profiles

(eV)

approximately

representative

however,

2.5

energy

of

approximately

same

stated

to

depth

of

also

have

Figure

a

FWHM

doses.

where of

t;; 3x10 incen-

a

2.5

30

3.5

4.0 45 5.0 ENERGY WI

5.5

60

6

‘2.5

30

3.5

40 4.5 50 ENERGY M/l

5.5

60

6.5

(b)

(a)

2.5

3.0

35

4.0 4.5 5.0 ENERGY WI

5.5

6.0

6.5

(cl

Figure

2.

with

a)

+Absorption

Cr

,

b)

Mn

+

spectra ,

and

2.5

Fe

C)

3.0

3.5

of +

v-SiO*

after

R.T.

implantation

ions.

4.0 4.5 5.0 ENERGY kV)

5.5

60

6.5

+ Fi Mn

f

ure ,

3. or

Fe+)

Variation of

in R.T.

absorption

implanted

v-SiO

s ectra 4

with

ion

specie

(C?

,

J. D. Stark

The

computer

initiated

simulated

by aforementioned

bands

being

in

the and

FWHM

tracted

from

above

parameters 4.

computer

simulated

centered

at

these

the

region

5.8

eV.

fit eV.

4.

Difference spectra

These unresolved

with

FWHM

0.44

ev,

in of

0.85

eV

both

of

which

observed

data

included

in FWHM

and spectrum, of

the

to a

spectal

were the

the spectra:

the were

fitted

E

'

the region at

two

ap-

regions:

approximately

6.5

the at

these

the

computer

two

M.

in

this

Figure

two

bands

band

at

FWHM

et

additional

al'.

of spectrum,

an

peak

of were

energies

experimental and

eV The

bands the

5.

that 4.8

with

Antonini

Examples of

of D

5.31'eV

constraining fit

shown

at

in

that a

subtracting

by

VSlUSS.

are

the

shown

seen

in

and

6.0

sub-

centered

excess eV

band

similarly above

were

regions:

presence

reptrted when

Lorentzian

spectra.

original and

in

by

indicate

computer-simulated fitting

is

eV,

using

be

region

4.5 5.0 5.5 ENERGY(eVI obtained

a

eV

0.6

are

two a

5.05

experimental

fitting, the

and fit

the

the

have

can

5.8

and

differences in

eV

spectra from

deficiencies

are

deficient

4.0

eV

computer

it

approximately

35

Figure

the

the

and

spectra the

was

contain eV

0.41 to

by

computer

at

5.05

of

assumed

of

4.8 The

the

spectra

is

spectra to

experimental

difference

centered

simulated

was

spectra

approximately 5.3

with

generated

the

689

absorption

FWHM

The

spectra and

From

eV

glass

spectra

with

eV 9band

0.82

the

bands

shape

7.15 of

the

proximately

of

o/ Si02

experimental

absorption

respectively;

Figure

the

Gaussian

spectra

fitting

assuming

three

shape

ef 01. / Optical

details

690

ENERGY WI Fig:re with

5. +

Cr

data;

Absorption ions.

Solid

dashed

tail

from

4.

DISCUSSION

forms: of

in

valence

two

two each

of

these optical

shape

for

all

the

fact

1000

nm,

supports

due

primarily

ra;$e

from

Fe

to

the region

measurement

and

+3.

absorption conclusion

of the

between of

in

the

The

spite

of is

also 400

to in

detected

large only only

in

due

1,000

the

to

"m. are

similar

shape,

in

the

its present

dose

similarity that

of two

present

given

as

in

absorption

range a

iron number

observed

optical

for

and

limited

been

is

of

the

first

combined range

absorption

400

spectra

transition

strengths of

due

one to

the

order the

.

was

of Cary

Fe

2+

0.2, 7.5 14.

the

bands

to are

the

holw4ever, eV Thus,

difficulties

transfer oscillator

region

of

1000

band

has

an

the which

peak is

of

ele-

transitions

charge with

in

series

observable

transfer

charge

and

for

(e.g.

forbidden

6.5

line.

damage.

ions

order band 2-b Mn

dashed

a

in Iron

This

no

partially a

+3 12

species.

oscillator

the

experimental

thick

chemistry,

spectra

the of

oxides,

of

and

radiation

case

(e.g. case

strength

that

in

has

soiytion

observed

ion

to

the in

-1

+2 is

implantation

manganese

ions

Manganese, in

absorption

with

ments

+6

+2

ions

chromium, metal

Chromium

states

forms:

The

In

and

forms:

valence

with

stateli,

+3

R.T. dots,

eV.

transion

oxidation

after

specrrum; bands;

melted these

chemical

number

best-fit

7.15

glasses,

valence


at

contain

equilibrium

2

v-SiO

computer-resolved

peak

Silicate

of

line,

lines, the

dopants,

in

spectrum

is

band

of

streiYths nm).

In

oscillator

located

beyond

the

in

detecting

in

the

range

of bands

who?;

o:zillator

110

strengths The

cm

be

a

valence

combination

the

charged

chat

there

even

though

suggest

no

its that

of

+2

for

oscillator of

+3.

ion

are

i.e.

+l,

is

to

and

higher

of

transfer

ions

fluxes

expected

Because

charge

iron

for

specie

and

the

strength

fraction

expected

ion state,

e.g.

evidence

the

are

each

as-implanted

states,

was

-1

~10

states

of

p.ositively

are

the

band

of

the

order

in

the

+3

state

by

the

fact

of of

+3

Fe

one,

we

is

very

small. From and

a

of

evident

and We

16

is

the

experienced

even

the

at

the

lowest

region

this each

is

absorp-

of

a

par-

of

specie

the

ion

with

the

substrate.

implanted

dose

the

implanted

As

a

consequence.

undergoes

it

effect

in

displacements.

implanted

presence

for

dose

3, of

the

in

atom

same

Figure

intensity

of

produced

each

multiple in

of

reactions

side),

in

the

reason

centers

that, per

affect

possible

damage

estim?te

produced shown

evidence

One chemical

ions/cm

glass

does

indirect

differing

substrate

spectra species

specie

specie.

is

specie

ion

hence ion

the

different

the

and

cicular

of

the

that

tion,

10

comparison

energy

a

(i.e.

1 X

region

has

the

SiO

transformation

in

2

StrUCtUre. 5.

CONCLUSIONS The

optical

radiation of

absorption

damage

detected.

This

tributed

to

partially

that

this

due

to

Figure to

The the

damage

ion was and

radiation

the specie

damaged

the to

implanted

growth

absorption

due

interactions

ions

the

and

2 damage

to

the

absorp-

We

suggest

absorption

is

glass. is

effect

between

the

dose.

optical SiO

This

implanted.

at-

of

of on

the

is

glasses.

of

of

ions

intensity

dependent

the

were

strengths

the the

linearly

ions

these

in that

evidence

implanted

oscillator

the

to &

dependent

of the

on

ion

specie

damaged

SiO

is and

2

species. detected Spectrosil

of damage

the

not

differing

concentration

low

restructuring ion

effect

to

present

evident of

of

to

No

is

intensity

different

the

primarily process.

involving

ions is

fundamental

attributed

(Spectrosil

it

due

due

of of

2

particular

due

absorption

non-linearity a

are

implantation

transitions

number due

with

of

combination

forbidden From

the

bands

lack

a

insufficient

the

by

absorption

optical

tion

spectra

caused

due

to

WF).

the

different

Thus,

impurities

(OH

and

Cl)

processes,

nor

the

interaction

substrate

material.

substrates

the

used in

differences do

not

influence of

ion

the the

specie

J D. Stork

692

et al. / dpticol

spectra

a/ SiO,

glaw

ACKNOWLEDGEMENTS The Ridge in

the

thank

J.

the

Moore

Laboratory

accelerator

with of

auth_ors National

Nashville

NSF travel

and Universities

Grant

for

and

discussions

by

State with

Jackson

programs

helpful

part

#W-7405-Eng-Za, Associated

J.

fitting

for in

the Solid assistance

his

laboratory,

computer

supported

at

for

advice

glass

input.

#DMR-8513731 support was

This and

DOE

provided

2.

J. Narayan. Appl. Phys.

3.

4.

J. 12

and Electron Beam Processing of and P.S. Peercy (Academic Press,

Fletcher, (1981)

C.W.

by

Ch.

Buchal. (1987).

and

W. H.

Christie,

J.

P. R. Ashley,

M. Williams, C. G. McHargue. B. R. Appleton, J. Appl.

and

and

8.

R.

Appleton.

J.

Mater.

Res

222.

5.

J:P. 146.

6.

R. A. Weeks, M. Sylva, B. R. Appleton, J. G. Kordas and D. L. Kinser, NRS Symposium, April 1985.

7.

R. A. Weeks, G. Whichard, XIV Intl. Congr. on Glass

8.

P. R. Physical

9.

M. Antonini, Effects ti

10.

Materials, New York,

7121.

H. Maramoco. C. W. White, J. 0. W. Holland, M. M. Abraham Phys. 55 (1983) 683. 2

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G. W. Arnold,

Phys.

Champagni, 41 (281). Transaction,

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(1983)

Martinelli, San Francisco, B. R.

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Nuclear

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for

the

Manara. NS20

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R. A.

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F. L. Harding, Introduction Stevens, LaCourse, (Plenum

J.

Appl.

Phys.

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(1960)

to Glass Science, ed. Press, New York-London

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by Pye, (1972)),

413.

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W. A. Weyl. Sheffield,

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Glass

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Am. Mineral.

help group

research

by

REFERENCES J. M. Poate, Laser ed. by C.W White (1979)), P-691.

Oak

end

research

(ORAU).

1.

of instruments

the

his

the

and

Division

59

was Contract

Oak

Ridge