Defects in single-crystal silicon induced by hydrogenation

Abstract

It is demonstrated that hydrogenation induces microdefects and electronic deep levels in single-crystal silicon, which are unrelated to either plasma or radiation damage. After hydrogenation of either n-type or p-type silicon, transmission electron microscopy reveals defects that can be described as hydrogen-stabilized platelets or microcracks which appear within 0.1 \ensuremath{\mu}m of the exposed surface and are predominantly oriented along {111} crystallographic planes. These defects correlate with high concentrations of hydrogen or deuterium as measured by secondary-ion mass spectrometry and with the appearance of Si---H bonds as revealed by Raman spectroscopy. The concomitant introduction of electrically active gap states is demonstrated with both photoluminescence spectroscopy (PL) and deep-level transient spectroscopy (DLTS). In PL several H-induced radiative transitions are observed, with the dominant peak at 0.98 eV, which had previously been ascribed to plasma damage. In n-type Schottky diodes, DLTS detects two H-induced levels with thermal activation energies for electron emission of approximately 0.06 and 0.51 eV. These defects are detected at depths greater than the surface layer, are in low concentrations (${<10}^{13}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$), are acceptorlike, and anneal with an activation energy of \ensuremath{\sim}0.3 eV.