μ-Raman Spectra Analysis of the Evolution of Hydrogen Related Defects and Void Formation in the Silicon Ion-Cut Process

Abstract

AbstractHydrogen implanted, boron doped (100) Czochralski silicon wafers, which were annealed after implantation up to 600 °C, are investigated by μ-Raman spectroscopy (μRS). We have studied the thermal evolution of hydrogen related defects, including vacancy-hydrogen (VnHm) complexes, H-saturated dangling bonds and trapped H2 molecules. Applying temperatures above ∼ 400 °C, the hydrogen related defects and the formation of voids/platelets are distinctly modified. The measured intensity of the local vibration mode (LVM) of H2 molecules trapped in multi-vacancy complexes at a frequency of ∼ 3820 cm-1 decreases while the LVM of H2 in platelets or larger voids (∼ 4150 cm-1) is increasing. This indicates that multi-vacancy complexes coalesce and form larger voids/platelets. Most of the VnHm complexes (∼ 2000 – 2200 cm-1) are dissolved during annealing at 600 °C, where a thin silicon layer exfoliates due to the ion-cut mechanism. However, the Raman modes of the characteristic V2H6 complex, of Si-Hx bonds stemming from H-terminated surfaces and of H2 located in voids/platelets still can be observed after a short time annealing (≤2 min) at 600 °C.