Defects in Ge caused by sub-amorphizing self-implantation: Formation and dissolution

High Resolution X-Ray Diffraction (HRXRD) was used to study the strain evolution of lattice defects formed in an array of B delta layers grown by Molecular Beam Epitaxy (MBE) and damaged by sub-amorphizing Ge self-implantation. The MBE structure was implanted at room temperature (RT) with 840 keV Ge at a dose of 1.5 × 1012 Ge/cm2. First of all, we observed a RT strain reduction of ~ 40% with respect to the strain value found in the just-implanted sample. This strain ageing phenomenon saturates in about 5 months. Then, the complete defects dissolution was monitored by in-situ HRXRD during isochronal annealings. Three others strain-recovery steps were identified, the last at T = 157 °C. Moreover, Secondary Ion Mass Spectrometry performed after the strain recovery did not detect any B diffusion till T was raised up to 840 °C, measuring in this case a B diffusion equal to the equilibrium one. The whole set of data will be discussed and compared with existing literature.