Investigation Of The Property Of N~+-Implanted Czochralski Silicon

Nitrogen has important effects on the properties of the single crystal silicon, and its properties, mechanisms on reactions with related defects and the effect on the electrics performance of silicon have been intensively investigated. In this paper, nitrogen was implanted into the silicon wafers, which were subsequently treated by rapid thermal processing (RTP) and then characterized by Optical microscope and fourier transform infrared spectroscopy. The effect of implantaion doses, implantation energy and annealing conditions on oxygen precipitate and induced defects as well as intrinsic gettering and electrics property in nitrogen implanted Czochralski silicon was studied.After analyzing the FTIR results of the nitrogen implanted silicon wafers processed by RTP at different temperatures, it was found that three infrared absorption bands at 799 cm-1, 998 cm-1 and 1018 cm-1 related to nitrogen-oxygen complexes appeared when the wafer processed in the 650~750℃temperature range. Nitrogen-vacancy complexes appeared when the temperature was at 800℃, and these absorption peaks had a certain stability. Nitrogen-oxygen couldn't form completely when the silicon sample processed by RTP. When the nitrogen implanted silicon was annealed at nitrogen atmosphere, nitrogen would diffuse into silicon wafers, nitrogen-oxygen and nitrogen-vacancy complexes absorption peaks corresponding increased.After nitrogen implanted into silicon with different implantation doses, the resistance of the silicon wafers decreased sharply, and the resistance became smaller when the implantation dose get bigger. Nitrogen implanted silicon can generate a kind of nitrogen related new donor which forms and disappears with the formation and disappearance of nitrogen-oxygen complex respectively. Nitrogen-new donor changed the resistivity of nitrogen implanted silicon. Nitrogen-oxygen had a certain stability, it can stability existed in the 650~750℃temperature range.In this work, the intrinsic getting in nitrogen implanted czochralski-silicon was studied. The result shows that a denuded zone at the surface of the nitrogen implanted czochralski-silicon wafer can be formed through one–step annealing. Stacking fault, dislocation and dislocation loop appeared in nitrogen implanted silicon after annealing at high temperature. These stacking faults and the dislocation grew and generated with the increasing annealing time. With increasing annealing time, the density of defects increased as well as DZ width increased too. The effect of the dose and energy of nitrogen implantation on the defect of silicon was investigated. The smaller implanted dose, the better of the denuded zone, and the smaller of the density of the defects. Also, when the implanted energy was smaller, the nitrogen was closer to silicon surface and it can out diffused faster, so the denuded zone would be better. RTP pre-annealing had important effect either, with the pre-annealing temperature rising, the density of the defect increased, the DZ width decreased and the length of the defect shortened.