Ming-Qi Meng

Analysis of refractive index profile in KTiOPO4 waveguide formed by 3.0 MeV He+ implantation

Abstract The optical waveguide formation in X-cut KTiOPO 4 was achieved by single energy implantation of 3.0 MeV He + to a total dose of 2.0×10 16 ions/cm 2 at liquid nitrogen temperature. The modes were examined by the prism (LiTaO 3 ) coupling method. The analysis of the refractive index profile in the KTiOPO 4 (100) waveguide was performed based on parametrized index profile reconstruction (PIPR). We have used the TRIM (the transport of ions in matter) code to simulate the energy loss distribution. The result shows that the nuclear collision mostly influences the refractive index profile, but the peak position of the refractive index profile is shallower than that of the nuclear energy loss distribution.

Double barrier waveguides in KTiOPO4 formed by MeV He ion implantation

KTiOPO 4 was implanted by 2.0 MeV and 2.8 MeV He ions with the same dose of 1.5 × 10 16 ions cm −2 to form double barrier waveguides. The dark modes were measured by prism coupling. We have used the method of Fluck et al . to fit the refractive index profile of double barrier waveguides in KTiOPO 4 . The close agreement between the measured and calculated mode indices indicates that the refractive index profile obtained for double barrier waveguides in KTiOPO 4 seems to be reasonable.

Rutherford backscattering/channeling study of the implanted MeV Au+ in silicon

Abstract 1.0 MeV Au + ions were implanted into a Si single crystal and an amorphous silicon film at room temperature. For the case of the Si single crystal, ion implantation was performed at angles of 7, 45 and 60°, respectively. The amorphous silicon film was deposited on SiO 2 substrate with a thickness of ∼500 nm. The longitudinal and lateral distributions of implanted Au ions in silicon were measured by Rutherford backscattering spectrometry. The lateral spread was estimated from the tilt angle implantation. The results show that the experimental mean projected range is larger than the calculated value by ∼20%, and the experimental range straggling and lateral spread deviate significantly from the TRIM prediction. The damage in the Si single crystal induced by MeV Au + under different fluences was studied by Rutherford backscattering/channeling. Also, the thermal behaviour of the implanted Au + in silicon was investigated.

Ion‐Implanted Planar Optical Waveguides in Nd:MgO:LiNbO3

Nd:MgO:LiNbO3 is a laser material. Planar optical waveguides in Nd:MgO:LiNbO3 were formed by He + implantation to doses of 1.4 x 10 -16 and 1.5 x 10 -16 ions/cm 2 at energies of 2.8 and 2.5 MeV, respectively, and dark modes were observed by the prism coupling method. The effect of MeV He ion implantation on the lattice order of the crystals in the guiding regions of the waveguides was analyzed by the Rutherford backscattering/channeling technique. The refractive index profiles are all calculated and fitted by using WKB method and PIPR method, respectively. The fluorescence spectrum of the sample has been measured.

DIFFUSION BEHAVIOR STUDY OF YB+ AND ER+ IMPLANTED INTO POLYIMIDE (C22H10N2O5)N

Polyimide (C22H10N2O5)n films were irradiated at room temperature by 200, and 300 keV Yb+ and 400 keV Er+. The dose was 1×1015 ions/cm2. The Rutherford backscattering technique has been used to study the diffusion behavior and the depth distribution of implanted Yb+ and Er+ in polyimide (C22H10N2O5)n. The results show that (1) for the sample annealed at lower temperature, the migration of Yb+ and Er+ into the overlying polyimide is faster than into the undamaged polyimide, but there is a significant non-Fickian tail extending deep into the undamaged polyimide film, (2) oxygen loss was observed, and (3) the depth distributions of “as implanted” Yb+ and Er+ were nearly Gaussian in all cases. The x-ray photoelectron spectroscopy was used to study the structural modification. After ion implantation, the binding energy of carbon 1s, nitrogen 1s and oxygen 1s in polyimide was decreased.

Investigation of radiation damage in germanium induced by MeV Si

Polished germanium Ge (100) was irradiated with 1.0–2.0 MeV Si+ at different doses from 4×1013 to 1×1014 ions/cm2 under different angles: 7°, 45°, and 60°. The radiation damage is studied by the Rutherford backscattering/channeling technique. The experimental damage distribution is extracted from the spectrum based on the procedure by Feldman et al. The experimental damage distributions are compared with the result from the TRIM (transport of ions in matter) code. The results show that (1) it is easier to amorphize Ge than Si, and the damage in Ge (100) induced by MeV Si+ depends on the dose, energy, irradiation angle, and annealing temperature also; (2) the shape of damage profile in Ge (100) induced by 2.0 MeV Si+ under 60° irradiation can be described well by the TRIM prediction, except the near-surface region where the experimental damage ratio is higher than that given by the TRIM prediction; (3) after 800 °C annealing, damaged Ge (100) trends to be recrystallized.

Double barrier structures in LiNbO3 waveguide created by MeV He+ implantation

Abstract The double barrier structures in a LiNbO 3 waveguide have been investigated by 3.2 MeV He + and 2.0 MeV He + implantation to the dose of 3 × 10 16 ions/cm 2 and 1.5 × 10 16 ions/cm 2 , respectively. The modes were measured using a prism (rutile) coupling method. The width of the modes is very irregular. The refractive index profile is analyzed based on the method by Fluck et al. [Appl. Phys. 74 (1993) 6023]. It is found that the measured mode indices of the waveguides are in agreement with the calculated mode indices. Also a damage study of double waveguides in LiNbO 3 was performed by a Rutherford backscattering/channelling technique. The result shows that the channeling spectrum in the guiding region of the first waveguide is little different from that of virgin LiNbO 3 crystal.

DETERMINATION OF THE LATERAL SPREAD OF XE IONS IN SILICON NITRIDE AND HYDRATED SILICON NITRIDE FILMS BY OBLIQUE INCIDENCE RUTHERFORD BACKSCATTERING

Both 100 and 200 keV Xe ions were implanted into silicon nitride (Si3N4) films and 600, 800, and 1000 keV Xe ions were implanted into hydrated silicon nitride (Si1N1.375H0.603) films at different angles. In order to determine the lateral spread of Xe ions implanted in Si3N4 and Si1N1.375H0.635 at room temperature, both normal and oblique incidence Rutherford backscattering were used. The results show that marked improvements in the measurement sensitivity to lateral spread is obtained by oblique incidence Rutherford backscattering. The lateral spread obtained agrees with the TRIM’92 prediction within experimental error for the 100–200 keV Xe+ implanted into the Si3N4 films, but a significant deviation of the lateral spread from the calculated value is observed for 600, 800, and 1000 keV Xe+ implanted into Si1N1.375H0.603 film.

The study of damage and optical properties in LiNbO3 implanted by MeV Er and He ions

Abstract Two LiNbO3 (X and Y cut) crystals from different companies were implanted by 3.0 MeV Er ions to a dose of 7.5 × 1014 ions/cm2 and 3.5 × 1014 ions/cm2 with different beam current densities, respectively. After annealing at 1060°C in air for 2 hours, one LiNbO3 sample was implanted by 1.5 MeV He ions to a dose of 1.5 × 1016 ions/cm2. The Rutherford backscattering/channeling and prism coupling method have been used to study the damage and optical properties in implanted LiNbO3. The results show: (1) the damage in LiNbO3 created by 3.0 MeV Er ions depends strongly on the beam current density; (2) after annealing at 1060°C in air for 2 hours, a good Er doped LiNbO3 crystal was obtained; (3) there is waveguide formation possible in this Er-doped annealed LiNbO3 after 1.5 MeV He ion implantation. It is suggested that annealing is needed to remove the damage created by MeV Er ions before the MeV He ion implantation takes place, to realize the waveguide laser for Er doped LiNbO3.

Range straggling and lateral spread of MeV Au+ ions in LiB3O5 and SiN1.375H0.603

Both LiB3O5and SiN1.375H0.603 were implanted by 1.0 MeV Au+ ions to a dose of 5×1015 ions cm-2 under different angles. The range straggling and lateral spread of 1.0 MeV Au+ ions in both LiB3 O5 and SiN1.375H0.603 were investigated by the Rutherford backscattering of 2.1 MeV He2+. The experimental mean projected range, range straggling and lateral spread are 279.7 nm, 54.0 nm and 34.6 nm for the case of LiB3O5, and 222.3 nm, 54.6 nm and 31.5 nm for the case of SiN1.375H0.603. The results show that the experimental range straggling and lateral spread are much larger than the values predicted by the 1998 version of the Transport of Ions in Matter code (TRIM98). After inelastic effects have been included in nuclear stopping regime, there is a much closer agreement with the experimental values than the original TRIM98 codes have. The maximum differences of the mean projected range, range straggling and lateral spread between experimental and calculated values are less than 3%, 24% and 21%, respectively for both cases.