Compositional dependence of damage buildup in Ar - ion

bombarded AlxGa1-xN

Karolina Danuta Pągowska

Soltan Institute for Nuclear Studies

2

1. Energy loss of ions in solids, collision cascade

2. Ion implanter

3. FET

4. RBS and channeling

5. Channeling spectra for ion bombarded GaN

6. Multi-step damage accumulation in irradiated crystals

7. Summary

Outline

3

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

En

erg

y

/ M

eV

Rp = 5.21 µm

Depth/ µm

0 1 2 3 4 5 6

Energy - Depth – Relation for 1.5 MeV He–ions in Si

4

1/2

d/d

(d/d)n

(d/d)e

200 keV Ar+

15 keV 2 MeV

0.9 keV He+ 800 keV 2 MeV

0.008 keV 70 keV 2 MeV

Ion velocity ~ (Energy)1/2

En

erg

y lo

s s

He ions

He ions

Ar ions

Ar ions Ionization

Displace-ments

dEe/dx

dEn/dx

Energy loss of ions in solids

5

Collision cascade

6

Target chamber

Wobbler

Magnetic lenses

Accelerator

Magnetic separator

Ion source

Extraction

Ion implanter

7

• Doping

• Insulating region formation (patterned implantation)

Mask

Ion beam

Sample

Ion implantation in compound semiconductors and their heterostructures in usually performed for:

8

Si substrate

Ion beam

Mask

Field – Effect Transistor (FET)

9SiO2 Si

SOI – Silicon On Insulator

10

Detector

x0

- O- Si

4He, 2 MeV

x0

Si SiO2

Energy

Depth

x0

Yie

ld

Principles of Rutherford Backscattering Spectrometry

11

Ion channeling

12

Short summary of HRXRD superlattice analysis

Defect analysis using ion channeling

13

Channeling spectra for ion implanted GaN

GaN

channel

100 200 300 400 500 600 700 800

yiel

d

0

500

1000

1500

2000

2500

3000 random 1*1017 4*1016 1*1016

5*1015 3.5*1015 2*1015

1*1015 5*1014 1*1014

5*1013 1*1013 5*1012 virgin

14

Experiment and simulation

Fluence 1*1015

energy200 400 600 800 1000 1200 1400

yiel

d

0

500

1000

1500

2000

experimentsimulation McChasy

15

Distribution of displacement atoms

Fluence 1*1015

depth (nm)

0 200 400 600 800 1000 1200

disp

lace

men

t ato

ms

%

0

2

4

6

8

10

12

14

16

18

16

Schematic representation of the MSDA model

Fluence

Acc

umul

ated

dam

age

FluenceA

ccum

ulat

ed d

amag

e

Fluence

Acc

umul

ated

dam

age

Structure A

Structure BStructure C

Structure A

Structure A

Structure B

Structure B

Structure C

Structure C

Structure A

Structure A

Structure A

Structure B

Structure B

Structure CA

B

A

B

B

C

Low fluenceStage 1

Medium fluenceStage 2

High fluenceStage 3

a

b

c

17

Simulation

fluence (x 1014)

0 20 40 60 80

accu

mul

ated

dam

age

0

20

40

60

80

100

simulationx3

x2 fd3

fd2

fd1

Simulation multi-step accumulation

18

For GaNfd1=6sig1=0.77fd2=68.5sig2=0.0398x2=12.5fd3=100sig3=0.008x3=400

Three-step accumulation

19

Three-step accumulation

20

For AlGaN

fd1=6

sig1=0.86

fd2=54

sig2=0.015

x2=5

Two-step accumulation

21

Two-step accumulation

22

Two-step accumulation

For AlNfd1=7sig1=0.245fd2=63.5sig2=0.02x2=10

23

Two-step accumulation

24

Summary

GaN Three-step accumulation

AlGaN Two-step accumulation

AlN Two-step accumulation

25

Thanks for attention