X-cut LiNbO3 crystals were implanted at room temperature by 5.0 MeV O3+ ions with doses ranging from 1.0×1014 to 6.0×1014 O/cm2. Secondary ion mass spectrometry profiles of atomic species migration as well as damage profiles by the Rutherford backscattering channeling technique and refractive index variation were investigated as a function of dose and subsequent annealing conditions. Two different kinds of damage produced by oxygen implantation were seen: near-surface damage correlated to electronic stopping, which causes an increase of the extraordinary refractive index, and end-of-ion range damage generated by collision cascades, which decreases the extraordinary refractive index values. The different nature of the two kinds of damage is also seen by the different temperature conditions needed for recovery. Low loss planar optical waveguides were obtained and characterized by the prism coupling technique.
The temperature and stress distribution induced in silicon wafers during ‘‘rapid isothermal’’ annealing have been calculated for two commonly used heating methods: (a) by a strip heater and (b) by uniform irradiation with an energy flux. Analytical expressions have been obtained for the temperature and stress profiles which show that thermoelastic effects, originated by the temperature drop at the sample edge, are much higher in case (b). The conditions of plastic deformation and consequent damage introduction have been established by comparing the yield stress with the value of stress resolved on the {111} planes in the 〈110〉 slip directions. As a result, the topographic distribution of the slip lines, the extension of the peripheral damaged region, and the temperature threshold for damage introduction have been evaluated for 2- and 4-in. wafers. Rapid isothermal annealing experiments have been performed to check the results of the calculations. Two-inch silicon wafers were irradiated uniformly for 15 sec in the temperature range from 930 to 1400 °C by using a shuttered electron gun. The threshold temperature for damage onset was found to lie in the interval 1030–1090 °C; the observed geometrical distribution of the slip lines and their extension were consistent with theoretical estimates.
The damage effects produced in the near-surface region of x-cut LiNbO3 by low dose, high energy implantation of carbon, nitrogen, oxygen, and fluorine ions are investigated as a function of the dose and substrate temperature during the implant process. The damage profiles were obtained by the Rutherford backscattering RBS-channeling technique, whereas the compositional profiles were performed by secondary ion mass spectrometry. The experimental results showed that the mechanisms governing the damage formation at the surface are strongly connected to the interaction of defects produced when the electronic energy loss exceeds a given threshold close to 220 eV/Å. In particular, we observed a damage pileup compatible with a growth of three-dimensional defect clusters
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