Karolina Danuta Pągowska Soltan Institute for Nuclear Studies Compositional dependence of damage buildup in Ar - ion bombarded AlxGa1-xN Karolina Danuta Pągowska

Outline 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

Energy - Depth – Relation for 1.5 MeV He–ions in Si Rp = 5.21 µm Depth/ µm 0 1 2 3 4 5 6

Energy loss of ions in solids He ions Ar ions Energy loss He ions Ar ions Ionization dEe/dx Displace- ments dEn/dx Ion velocity ~ (Energy)1/2

Collision cascade

Ion implanter Target chamber Wobbler Magnetic lenses Accelerator Magnetic separator Ion source Extraction

Ion implantation in compound semiconductors and their heterostructures in usually performed for: Doping Insulating region formation (patterned implantation) Mask Ion beam Sample

Field – Effect Transistor (FET) Si substrate Ion beam Mask

SOI – Silicon On Insulator SiO2 Si

Principles of Rutherford Backscattering Spectrometry Energy Depth x0 Yield x0 Detector - O - Si 4He, 2 MeV x0 Si SiO2

Ion channeling

Defect analysis using ion channeling Short summary of HRXRD superlattice analysis

Channeling spectra for ion implanted GaN

Experiment and simulation

Distribution of displacement atoms

Schematic representation of the MSDA model Structure A Structure B Structure C A  B B  C Low fluence Stage 1 Medium fluence Stage 2 High fluence Stage 3 a b c

Simulation multi-step accumulation

Three-step accumulation For GaN fd1=6 sig1=0.77 fd2=68.5 sig2=0.0398 x2=12.5 fd3=100 sig3=0.008 x3=400

Three-step accumulation

Two-step accumulation For AlGaN fd1=6 sig1=0.86 fd2=54 sig2=0.015 x2=5

Two-step accumulation

For AlN fd1=7 sig1=0.245 fd2=63.5 sig2=0.02 x2=10 Two-step accumulation For AlN fd1=7 sig1=0.245 fd2=63.5 sig2=0.02 x2=10

Two-step accumulation

Summary GaN Three-step accumulation AlGaN Two-step accumulation AlN

Thanks for attention