Amorphization of silicon via electronic processes induced by irradiation with fullerenes

For the first time it is shown that single crystalline silicon is sensitive to collective electronic excitations. Irradiations with C60 clusters accelerated in the 10 MeV range induce the formation of amorphous latent tracks in this material. This result has never been observed with high energy heavy ions, it means that what may matter is the very high electronic energy density deposited in the silicon by the incident cluster. TEM (transmission electronic microscopy) analysis of irradiated samples have enable us to measure surface damage cross-sections: 55 nm2 and 87 nm2 for irradiations with C602+ beams and C603+ beams accelerated respectively to 30 and 40 MeV. (A.C.)