Solid-phase epitaxy of silicon amorphized by implantation of the alkali elements rubidium and cesium

Abstract

Studies on atomic layer deposition Al2O3/In0.53Ga0.47As interface formation mechanism based on air-gap capacitance-voltage method Appl. Phys. Lett. 101, 122102 (2012) A mathematical model for void evolution in silicon by helium implantation and subsequent annealing process J. Appl. Phys. 112, 064302 (2012) Void evolution in silicon under inert and dry oxidizing ambient annealing and the role of a Si1−xGex epilayer cap J. Appl. Phys. 112, 054909 (2012) Additional information on AIP Conf. Proc. Abstract. The redistribution of implanted Rb and Cs profiles in amorphous silicon during solid-phase epitaxial recrystallization has been investigated by Rutherford backscattering spectroscopy and secondary ion mass spectroscopy. For the implantation dose used in these experiments, the alkali atoms segregate at the a-Si/c-Si interface during annealing resulting in concentration peaks near the interface. In this way, the alkali atoms are moved towards the surface. Rutherford backscattering spectroscopy in ion channeling configuration was performed to measure average recrystallization rates of the amorphous silicon layers. Preliminary studies on the influence of the alkali atoms on the solid-phase epitaxial regrowth rate reveal a strong retardation compared to the intrinsic recrystallization rate.

Out-diffusion of cesium and rubidium from amorphized silicon during solid-phase epitaxial regrowth

“…During annealing of amorphous silicon, a redistribution of the implanted cesium and rubidium occurs which is caused by segregation at the a/c-interface during its movement towards the surface [4]. In this way a fraction of the implanted ions is pushed ahead towards the surface and is supposed to diffuse out.…”

“…Based on the results of these preliminary experiments, the implantation parameters for subsequent experiments may be modified for a comparison of the influence of both alkali elements. Wafer preparation, beam power, and implantation angle adjustment were chosen as described in [4] in order to avoid undesirable influences on recrystallization. The wafers were finally cut into 1.5 cm 2 pieces for the out-diffusion experiments.…”

“…Using spacers, both samples were placed face to face at a distance of 500µm. The setup was then annealed in a rapid thermal processing (RTP) system as described in [4]. For both elements, an annealing period of 15 minutes at 600°C was applied.…”

“…For both elements, an annealing period of 15 minutes at 600°C was applied. To ensure a full SPER, recrystallization times have been determined before these experiments by multistep recrystallization as described in [4].…”

“…Moreover, handling of hazardous alkali elements can be avoided by using less dangerous source feed materials. Previously, the redistribution of Cs and Rb during solid-phase epitaxial regrowth (SPER) of amorphous silicon has been investigated [4]. In this paper, the out-diffusion of implanted cesium and rubidium during SPER of amorphous silicon is investigated.…”