Shi-Jie Ma

Depth distribution and thermal stability of implanted Hg ions in silicon

50–400 keV Hg+ was implanted into silicon seven years ago. The depth distribution and temperature effect of the implanted Hg+ were recently investigated by Rutherford backscattering of 2.1 MeV 4He2+. The results show that the implanted Hg+ in silicon is still stable at room temperature after seven years. After 1000 °C annealing, the implanted Hg ions disappeared. The depth distributions of implanted Hg+ in Si can be well described by the transport of ions in matter (trim’90). In addition, the values of mean projected range and range straggling obtained from the present measurements are compared with those of TRIM’90 and the calculation procedure based on Biersack’s angular diffusion model.

Diffusion, evaporation and recrystallization in Hg-implanted amorphous Si

Abstract Silicon wafers were amorphized by 2 × 10 15 Ar + /cm −1 and 3 × 10 17 Ar + /cm −2 (abbreviated by a -Si and a -Si(Ar), respectively) and subsequently implanted with 400 keV Hg + to a dose of 4 × 10 15 ions/cm −2 . The diffusion and evaporation of the implanted Hg and recrystallization of the Hg-implanted amorphous Si have been studied over the temperature range of 700–1000°C by MeV He ion Rutherford backscattering/channeling technique. It is found that at 700°C, thermal diffusion dominates and there is no loss of implanted Hg in a -Si. The diffusion coefficient obtained is 7.8 × 10 −15 cm 2 s −1 . Above 800°C, the evaporation is a dominant mechanism. At 1000°C, the implanted Hg disappears. Recrystallization phenomena is also observed. But for a -Si(Ar) at 700°C, 87% of the implanted Hg is lost and at 800°C the Hg disappears totally. The remaining Ar segregates towards the surface and amorphous-crystalline interfaces.

Damage behavior of silicon by MeV Ge+ irradiation under tilted angle

The damage behavior of Si induced by MeV Ge+ under tilted angle has been studied. In order to investigate the effect of implanted energy and angle on the damage distribution, the energies were varied from 1 to 2 MeV and the angles were varied from 7° to 60°. The experimental damage distribution is extracted based on the procedure by Feldman and Rodgers [L. E. Feldman and J. W. Rodgers, J. Appl. Phys. 41, 3776 (1970)] using the multiple‐scattering model. The experimental data obtained are compared with the TRIM’90 code. The results show that the lateral damage spread can not be neglected; the shape and the depth of damage distribution are well described by the TRIM’90 code under tilted angle irradiation for Si(100).

Dechannelling analysis of damage in Si created by MeV Ti ions

The Rutherford backscattering/channelling technique of 2.1 MeV He ions has been used to study the damage distribution in Si irradiated with 1.0 MeV Ti ions to a dose of 5*1014 ions cm-2 under 7 degrees and 60 degrees incidence. A dechannelling analysis of multiple scattering has been made. The longitudinal damage straggling and lateral damage spread are estimated. The values obtained are compared with transport of ions in matter. The results show that the differences between experimental and calculated values for longitudinal damage straggling and the lateral damage spread are 25% and 28%, respectively. Also, it is observed that the damage distribution shape under 60 degrees irradiation is found in good qualitative agreement with an earlier simulation.

Damage profiles in silicon tilt angles bombarded by high energy Cu ions

High energy (MeV) Cu ions were implanted into n‐type Si samples at angles of 7°, 30°, 45°, and 60°. The doses were 5×1014 and 2×1014 ions/cm2. The damage profiles in Si(100) were investigated by a Rutherford backscattering/channeling technique with 2.1 MeV He ions. The longitudinal damage straggling and lateral damage spread are estimated for 1.0 MeV Cu+ implanted in Si(100). The values obtained are compared with the trim (transport of ions in matter) code. The results show that the longitudinal damage straggling is found to be in good agreement with the calculated one within 13% by use of the trim code, but the experimental value of the lateral damage spread is higher than the calculated one by about 28% using the trim code. The effect of dose rate, energy, and dose on damage distribution is investigated also.