The microstructure and electrical properties of hydrogenated Czochralski silicon treated at high temperature–pressure

Abstract

Annealing at up to 1400 K of hydrogen plasma etched Czochralski silicon (Cz-Si:H) under enhanced hydrostatic pressure (HP) up to 1.1 GPa (HT–HP treatment) results in specific effects related both to the presence of hydrogen and to enhanced HP. The latter strongly affects the sample microstructure, precipitation of oxygen interstitials and creation of thermal donors (TDs). The HT–HP induced effects in Cz-Si:H are related to the HP stimulated creation of nucleation sites for the creation of TDs and oxygen precipitation as well as to decreased hydrogen out-diffusion under HP.

Porous‐like structures prepared by temperature‐pressure treatment of heavily hydrogenated silicon

“…1) on the surface of Si:H annealed at 720 -1070 K under 10 5 Pa for 1 -10 h (their formation is related to rapid removal of hydrogen at annealing); similar effect has been reported for RSi:H [5]. The under -surface Si:H areas (at a depth of about 300 nm, corresponding to the projected range of H + , R pH ) are exposed in effect of cracking of such bubbles.…”

“…2) while decreases with HT. In the case of HT -HP treated RSi:H samples, their microstructure is dependent on HP and t in a similar way [5]. As-implanted Si:H as well as as-etched RSi:H indicate PL at about 1.1 eV originating from bound exciton recombination.…”

“…Much less bubbles of smaller diameters (of about 1µm) are created in Si:H treated under HP; blisters were practically non-detectable in Si:H if treated at 920 / 1070 K -1.1 GPa for 5 h. This is evidently related to a decreased diffusivity of hydrogen under HP [7]. Similarly as in the case of Si:H, the creation of blisters on the surface of RSi:H is markedly retarded under HP, especially at ≥ 1070 K [5]. High dose hydrogen implantation of Si using the immersion plasma source of ions results in a creation of hydrogenated amorphous layer just near the sample surface [8].…”

“…1) at about 300 nm depth; structural defects of the near -surface disturbed area reached the sample surface. Annealing under 10 5 Pa of Si:H as well as of RSi:H leads to pronounced oxygen accumulation within the hydrogen-enriched areas owing to extremely high gettering activity of the hydrogen-enriched areas at enhanced temperature (see [5,7]). In the case of HT -HP treated Si:H, the X-Ray diffuse scattering intensity increases with HP (compare Figs 2A with 2B and 2C) and treatment time, t (Figs 2C and 2D) but decreases with HT.…”

“…For the reference reason, other Cz-Si samples (in what follows denoted as RSi:H) were enriched in hydrogen (c H ≤ 0.5 at.%) to a depth of about 0.25 µm by hydrogen plasma etching at 533 K (H 2 flux of about 200 sccm, 110 MHz frequency, power 50 W, under pressure of about 50 Pa) [5]. The Si:H and reference RSi:H samples were subjected to the treatment in Ar atmosphere [6] at high temperature (HT ≤ 1400 K) under high hydrostatic pressure (HT ≤ 1.1 GPa) for 45 min.…”