V - Positron Annihilation in Halle

More documents

Recommendations

Info

positron lifetime (pss) Improved depth resolution by using a positron microbeam τ defect τ bulk positron microbeam E = 8 keV • We used Munich positron microscope p • Sample polished wedge-like scan direction (wedge angle 0.5…2°) • Defect depth profile of 10 µm μ α = 0.6° lateral resolution 1 ... 2 μm becomes as long as 1 mm • Thus, depth resolution con be optimized by wedge angle defect depth 10 m Martin-Luther-Universität Halle 0 1 mm scan width
First defect-depth defect depth profile using a 0,6 positron microprobe 0,4 • 45 lifetime spectra were recorded along wedge d • Because of beam diameter - depth resolution of 155 nm is obtained at α = 0.81° • Positron implantation energy: 8 keV ⇒ mean information depth 400 nm • OOptimum i ddepth h resolution l i • Both defected regions well visible • Vacancy clusters with increasing density down to 2 µm (Rp/2 region) • At R p region: lifetime τ2 = 330 ps; open volume corresponds to a divacancy; must be stabilized or being part of dislocation loops R. Krause-Rehberg et al., Appl. Phys. Lett. 77 (2000) 3932 Martin-Luther-Universität Halle η τ 2 (ps) averagee lifetime (ps) ( 0,8 450 400 350 380 360 340 320 300 260 0 1 2 3 4 5 6 microvoids R p /2 R p fraction of trapped positrons defect-related lifetime divacancy-type defect Silicon self-implantation - 3.5 MeV, 5×10 15 cm -2 - annealed 30s 900°C - Cu contaminated Cu SIMS-Profil 280 surface bulk silicon 0 1 2 3 4 5 6 ddepth th( (µm) )
Page 1 and 2: Defect Characterization in Crystall
Page 3 and 4: • Vacancy concentration in therma
Page 5 and 6: Defects in electron-irradiated elec
Page 7 and 8: GaAs: annealing under defined As As
Page 9 and 10: Comparison of doped and undoped GaA
Page 11 and 12: Theoretical Calculation of Vacancy
Page 13: Defects after high energy Si self s
Page 17 and 18: Determination of Defect Type 280
Page 19 and 20: Coincidence Coincidence-Doppler Dop

V - Positron Annihilation in Halle

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?