改善晶闸管薄发射区体压降的研究

Improving the Bulk Voltage Drop in the Thin Emitter Region of Thin Emitter Thyristors by the Polysilicon Film

就多晶硅接触薄发射极和金属接触薄发射极两种发射极对晶闸管薄发射区体压降Ｖ＿（ｂＥ）的影响进行了分析比较，结果表明：多晶硅接触薄发射极结构由于改善了接触处的界面状况，且由于多晶硅层对少子运动的障碍作用，使薄发射区内有效少子寿命大大提高，从而使Ｖ＿（ｂＥ）降至最小以致可忽略不计，这已为实验结果所证实。分析还表明：多晶硅的少子寿命是保证上述效果的关键参数。

The influences of two different thin emitter structures,the polysilicon-contacted andmetal-contacted structures,on the bulk voltage drop in the thin emitter region(VbE)of thinemitter thyristors are discussed.It is shown that,owing to the improved interface state atcontact in the polysilicon-contacted thin emitter and the obstruction of the polysilicon layerto the migration of the minority carrier,the effective lifetime of the minority carrier in thethin emitter region is greatly lengtlietied,thus reducing VbE to a negligible minimum. Thishas been verified by experiment.It is also shown that the lifetime of the minority carrier inthe polysilicon layer is the key pararneter to the above-mentioned mechanism.