Control of Optical Performance from Er-Doped Alumina Synthesized Using An Ecr Plasma
- PDF / 514,687 Bytes
- 6 Pages / 414.72 x 648 pts Page_size
- 56 Downloads / 158 Views
chamber to excite the 02 gas, forming neutral atoms and molecular ions. The energetic 02+ (-30 eV) stream down from this plasma generation region onto the layer and substrate. The ECR system base pressure was :0.3x10-8 Torr, and the operating pressure was 3-5x1 0-5 Torr with an 02 gas flow rate of 2.5 sccm. Evaporation rates for Al and Er were measured simultaneously using two quartz crystal monitors, and films were grown at 0.2 nm/s for Al while simultaneously evaporating Er at 0.01-0.03 nm/s. Hydrogen from the chamber walls is introduced into the films during deposition as a result of the interaction between the energetic plasma and the chamber. The hydrogen content of the films was measured, using elastic recoil detection, as a function of isochronal annealing treatments. This data was fit to a simple trap-release model in order to determine an effective activation energy for the thermal release of H from alumina. The composition of the films was determined using 2.8 MeV He+ Rutherford Backscattering spectrometry (RBS) at a scattering angle of 1640, and by using 16 MeV Si÷3 Elastic Recoil Detection (ERD) at a scattering angle of 300. Two isochronal annealing times were examined in this experiment in order to test the effects of kinetics on the trap-release model: 30 min. and 4 hrs. The samples were annealed ina vacuum < 5x10-8 Torr over the temperature range of 400 to 700 0C. The intensity of ion-beam stimulated luminescence (IL)from the samples annealed for 4 hrs. was then monitored at room temperature in the visible and near infrared regions as a function of the thermal treatments. The ILspectra examined inthis paper were obtained from samples containing 4 at.% Er. A 2.8 MeV He+ ion beam was used as an ILexcitation source with the beam incident at an angle of 450 from the sample normal. The range of these ions inA1203 is 6.4 pm, and therefore the He+ ions traverse the 300 nm thick films coming to rest deep in the Si substrate and lose energy inthe films primarily through electronic stopping. The emitted ILlight was focussed into an optical fiber bundle using a lens 1.25 cm from the sample and with the lens optic axis oriented along the sample normal. The collected light was guided into an Instruments SA HR320 monochromator containing a 150 lines/mm grating and the IL spectrum was then detected with a thermoelectrically-cooled CCD area-array photodetector. The resolution of this detection system was _ 2 nm. This equipment allowed six samples to be mounted and analyzed without breaking vacuum or changing the excitation/light-collection geometry, thereby allowing relative changes inemission intensity to be examined. The incident ion current was held constant at 200 nA/cm 2 during the ionoluminescence experiments. The ILspectra were collected for times of 10 s and 120 s at repeated intervals over the course of a day inorder to examine possible beam-damage effects. The intensity of the ILspectra was unaffected by ion beam fluences up to 3x10 15 He/cm 2. RESULTS AND DISCUSSION As stated above, the samples examined in
Data Loading...
