等离子浸没离子注入陡脉冲前后沿效应及控制技术  

The reduction of leading- and trailing-edge of high-voltage steep pulse in plasma immersion ion implantation

作　　者：朱宗涛[1] 桂刚[1] 汪志键[1] 巩春志[1] 杨士勤[1] 田修波[1] 

机构地区：[1]哈尔滨工业大学现代焊接生产技术国家重点实验室,哈尔滨150001

出　　处：《核技术》2010年第12期923-927,共5页Nuclear Techniques

基　　金：国家自然科学基金(50773015和10775036)资助

摘　　要：等离子浸没离子注入过程中,由于电路和负载的容性效应,使高压脉冲电源的输出电压前后沿较长,而高压脉冲的前后沿对离子能量的均匀性、注入深度及剂量分布都有很大影响。本文用硬管调制技术研制最高输出电压40 kV的脉冲电源,并通过一维PIC仿真方法,研究了脉冲后沿对注入离子能量的影响,并从理论上计算不同工艺参数下电源输出电能的利用率。对于前沿,当高压电子管一栅电压为200 V时,获得1μs的高压脉冲前沿时间。对于后沿,用多个IGBT开关串联释放高压脉冲关断后负载上存储的剩余电荷,获得较小的回复时间,实现了对高压脉冲拖尾时间控制。通过PSPICE仿真优化了脉冲后沿控制电路的驱动延迟时间和IGBT吸收电路的参数。During plasma immersion ion implantation （PIII） processes, due to the capacitance effect of the coaxial cable and plasma load, the output voltage pulse of high-voltage modulator possesses a longer leading- and trailing-edge time. The leading- and trailing-edge of the high voltage （HV） pulse have a critical effect on the ion-energy uniformity, depth and dose distribution during PIII processes. In this work, a tetrode was used as a hard tube to switch the DC high voltage, and a HV pulse modulator with a maximum pulse voltage of 40 kV was built successfully. The effect of the trailing-edge time on the implantation uniformity was simulated by one-dimension PIC method. The potential on the control grids of the tetrode was optimized to obtain a HV pulse with a short rise time. In our system, 200 V potential on grid one is utilized and the leading-edge time of pulse can be as small as 1μs. The IGBTs in series was utilized to release the remnant charges reserved in the equivalent capacitance of the plasma load and coaxial cable. Thus the trailing-edge time of the HV pulse could be reduced. The effect of the driver signals with different delay time and the absorption parameters of each IGBTs were simulated by PSPICE software to optimize the design the electric circuit.

关 键 词：等离子体离子注入 高压脉冲电源 陡脉冲 注入均匀性 

分 类 号：TG174.444[金属学及工艺—金属表面处理]