Combined lifetime killing by platinum and fast light ions in silicon power diode : thermal stability of introduced radiation defects
The influence of combined lifetime killing by platinum in-diffusion and fast light ion irradiation on generation and stability of introduced radiation defects was investigated in the low-doped n-type float-zone oxygen rich silicon forming the base of power pnn diodes. Different concentrations of platinum substitutionals were introduced by platinum implantation and subsequent annealing at temperatures ranging from 725 to 900°C. Diodes were then irradiated with 1.8 MeV protons or 5 MeV alphas to fluences ranging from 5x10 to 1x10 cm. The influence of platinum doping on introduction rates of dominant radiation defects and their thermal stability during subsequent isochronal annealing was investigated by deep-level transient spectroscopy. Results show that the presence of platinum atoms significantly influences introduction rates of dominant recombination centers introduced both by hydrogen and helium irradiation (vacancy-oxygen pairs, divacancies and VOH complexes). Simultaneously, temperature stability of vacancy-oxygen pairs and divacancies decreases of up to 150°C. In both cases, these effects are proportional to platinum concentration introduced into diodes.
Radiation Defects in Silicon: Effect of Contamination by Platinum Atoms
The influence of platinum contamination on the stability of radiation defects produced by high-energy proton irradiation was investigated in the low-doped n-type float-zone oxygen rich silicon forming the base of power p+nn+ diodes. Platinum was first implanted and then in-diffused at different temperatures to obtain different levels of contamination. Diodes were then implanted with 1.8 MeV protons to a fluence of 2x1010 cm-2 and radiation defect reaction during isochronal annealing were investigated by deep-level transient spectroscopy. Results show that contamination of silicon by platinum atoms influences significantly both the introduction rates and the temperature stability of dominant radiation defects (vacancy-oxygen pairs, divacancies and VOH complexes).
The Analysis on Fire Smoke Exhausting Robot Vibration Based on Wavelet Transform
Belt relaxation, which affects a lot on operation reliability of the fire smoke exhausting robot, is hard to detect. In this paper, a new method for belt relaxation feature recognition based on continuous wavelet transform (CWT) is proposed, and a vibration model which simplified the robot as a 2-dof forced vibration system under harmonic excitation is established. The vibration acceleration signal has been collected using the IEPE sensor and data acquisition card, experimental results verified the accuracy of the vibration model, and weak impact signal caused by the belt relaxation was distinguished, that testify the practicability of the CWT method in belt relaxation feature recognition.