Study of unidirectional conductivity on the electrical discharge machining of semiconductor crystals
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- 作者：Qiu Mingbo ; Liu Zhidong ; Tian Zongjun ; Wang Wei ; Huang Yinhui
- 关键词：Semiconductor crystals ; Electrical discharge machining ; Unidirectional conductivity ; Schottky barrier ; Circuit of resistances and diodes
- 刊名：Precision Engineering
- 出版年：2013
- 出版时间：October, 2013
- 年：2013
- 卷：37
- 期：4
- 页码：902-907
- 全文大小：1270 K
文摘
This paper investigates the unidirectional conductivity of semiconductor crystals machined by electrical discharge machining (EDM) by analyzing the properties of current-voltage (I-V) curves of the equivalent circuit. The simplified equivalent circuit of a semiconductor EDM consists of reverse-biased diodes and linear resistance. The I-V curve has three typical parameters, namely, conduction angle, breakdown angle, and breakdown point. The values of the conduction angle and the breakdown point are determined by the contact area of the reverse-biased diode, and the breakdown angle is determined by the value of linear resistance. Two diodes exist in the model with two metal electric feeders. To increase the current in this model, the diode with larger contact area should be reverse-biased. If the work piece is connected to anode in semiconductor EDM, the diode in the conduction side is reverse-biased and the avalanche voltage is only 42 V. If the work piece is connected to the cathode in semiconductor EDM, then the arc plasma, which is a termination with a small area, becomes reverse-biased. The temperature in the arc plasma side is high, causing the breakdown voltage to be much higher than the theoretical calculation value 88.5 V. As a result, when the work piece is connected to the cathode, spark production is difficult. Holes are bored on the P-type semiconductor crystals by positive and negative polarity, which could prove that machining with positive polarity is suitable for P-type semiconductor crystals during EDM. When the no-load voltage is set to 150 V, the penetration speed by positive polarity can reach 533 ¦Ìm/min.