Research Of Automotive Avalanche Rectifier Diode

Automotive avalanche rectifier diodes used in the automotive alternator rectifier circuit, normal operation is a common rectifier diode, the alternating current into direct current; When the car circuit fault induced transient voltage, avalanche rectifier diodes pass anti-Wizard, the avalanche voltage clamp at this time Rectifier diode breakdown voltage near the maximum to avoid damage to critical electronic components in the circuit.Automotive avalanche rectifier diodes operate in harsh environments, making performance of these diodes are more stringent requirements than normal diode, it needs a good high temperature properties, thermal fatigue demanding, high reverse surge capability, which makes automotive avalanche rectifier Diode in the manufacturing process to be different from the ordinary rectifier diode.In order to obtain good performance automotive diodes, This paper studies the characteristics of avalanche diodes, the reverse surge capability and capacity of thermal fatigue, Also the theoretical design of the diode, combined with graded junction and the abrupt junction formula to calculate the voltage required design selected resistivity, junction depth and other parameters. With actual production conditions, to submit a reasonable car avalanche rectifier diode manufacturing process, and concluded as follow:1. Select the original chip as low resistivity N-type chips, spread long enough to get the required voltage, so that the diodes produce a good reverse surge capability.2. Process to reduce the introduction of the stress, avoid using common process in the blowing sand approach to B-SI glass. Blowing sand caused by the silicon surface mechanical damage to the diode internal injuries caused irreparable. Therefore, power devices should be used instead of the electrolysis process.3. Phosphorus boron diffusion process at high temperature, due to impurity atoms and the silicon atoms of different sizes, causing great stress, so that the chip deformation serious. The slow diffusion process and annealing temperature can effectively reduce the internal stress.