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

Abstract

Hydrogen 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 (V n H m ) complexes, H-saturated dangling bonds and trapped H 2 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 H 2 molecules trapped in multi-vacancy complexes at a frequency of ~ 3820 cm -1 decreases while the LVM of H 2 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 V n H m 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 V 2 H 6 complex, of Si-H x bonds stemming from H-terminated surfaces and of H 2 located in voids/platelets still can be observed after a short time annealing (≤ 2 min) at 600 °C.

µ-Raman Investigations on Hydrogen Gettering in Hydrogen Implanted and Hydrogen Plasma Treated Czochralski Silicon

“…para-H 2 with anti parallel nuclear spin and an even quantum rotational number of 0 and 2 with LVM of 4161 cm -1 and 4143 cm -1 , respectively and ortho-H 2 with parallel nuclear spin and an odd quantum rotational number of 1 and 3 with LVM of 4155 cm -1 and 4125 cm -1 , respectively [18,20]. One can assume that hydrogen diffuses from small vacancies or multi-vacancies to large ones and that vacancies diffuse and coalesce, respectively [24]. The plasma hydrogenated samples exhibit a strong peak around ~2095 cm -1 , which indicates SiH x bonds of extended inner surfaces of platelets.…”