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从VDMOS器件EAS测试的原理出发,通过统计实际生产中出现的EAS不良现象,得出EAS测试不良的两种主要现象,一种为EAS测试后器件烧毁,显示PRE-SHORT损坏提示,第二种为EAS测试不通过显示POST-SHORT损坏提示,但器件没有烧毁。分别从器件源胞结构,以及EAS测试的时序上对两种不良现象的产生原因进行分析,得出源胞结构中的寄生电阻RB大,器件的Tf大是造成两种EAS不良的原因,提出通过提高Pbody浓度来降低源胞结构中的寄生电阻RB,并结合TCAD仿真,提出提高Pbody浓度来降低器件的Tf。最后通过对比实验验证不同Pbody浓度对器件EAS特性的影响,得到增加Pbody浓度可以有效提高器件EAS通过率与极限耐量。
Based on the principle of EAS testing of VDMOS devices, two major phenomena of poor EAS test are obtained through statistics of EAS defects occurred in actual production. One is the device burnout after EAS testing, which indicates PRE-SHORT damage prompts. The second The test for EAS does not show the POST-SHORT damage prompt, but the device did not burn. From the source cell structure of the device and the timing of the EAS test, we analyzed the cause of the two kinds of adverse phenomena and found that the parasitic resistance RB in the source cell structure is large and the Tf in the device is the cause of the two kinds of EAS defects. By increasing the concentration of Pbody to reduce parasitic resistance RB in the source cell structure, combined with TCAD simulation, it is proposed to increase the Pbody concentration to reduce the Tf of the device. Finally, the effect of different concentrations of Pbody on the EAS characteristics was verified by comparative experiments. Increasing the concentration of Pbody can effectively improve the EAS pass rate and ultimate tolerance of the device.