Crystalline material was irradiated with 60 and 80MeV Si ions, and regions of high defect density were located by repeatedly etching the sample and measuring the minority carrier lifetime. The lifetimes before etching were 10 and 8μs on 60 and 80MeV ion-irradiated sides, respectively. They were equal to 19μs on the non-irradiated side. Upon etching the samples, the values for the irradiated side first increased slowly but later increased steeply as the total thickness of the etched Si approached the ion range. The minority carrier lifetime on the non-irradiated side remained unchanged, even after etching. These results showed that the regions of high defect-density were situated at depths of 20 and 27μm, respectively, in 60 and 80MeV ion-irradiated samples. These coincided with the respective projected depths at which 60 and 80MeV Si ions deposited the maximum amount of energy via nuclear collisions.

S.T.Chavan, S.D.Dhole, V.N.Bhoraskar, D.Kanjilal, G.K.Mehta: Journal of Applied Physics, 1997, 82[12], 4805-9