An experimental study was made of the structural lattice damage caused by ion implantation. Using strain and disorder profiles, deduced from X-ray diffraction and ion-channelling experiments, defect accumulation was investigated as a function of ion fluence, mass, energy and current density. The damage accumulation process could be divided into 3 regimes; based upon the ion fluence. In the lowest-fluence regime, the strain and defect fraction were linearly proportional to the ion fluence and the number of defects in the implanted layer was directly related to the deposited energy that went into the creation of vacancies. In the second regime, the damage accumulation process was more efficient, due to the increased defect density in the implanted layer. The third fluence regime began at the critical fluence for amorphization. The latter value was determined for a wide range of ion masses and energies. A recovery study of the implantation-induced damage revealed 2 distinct annealing steps. Rapid thermal annealing at as low as 100C resulted in the removal of isolated defects, which were present in the low-fluence implanted samples, as well as in the tail of the implantation profile of heavily damaged samples. Annealing at 350C resulted in the recrystallization of amorphous Ge at the amorphous/crystalline interface at a rate of 14nm/min. Although Ge amorphized at much lower fluences than does Si, the influence of the implantation parameters upon damage accumulation was comparable for both semiconductors.

Implantation-Induced Damage in Ge: Strain and Disorder Profiles during Defect Accumulation and Recovery. S.Decoster, A.Vantomme: Journal of Physics D, 2009, 42[16], 165404