轴承滚珠等离子体浸没离子注入过程的数值模拟(5)

利用轴对称PIC模型对轴承滚珠等离子体浸没离子注入(PIII)过程进行了数值模拟,对归一化电势的扩展情况进行了研究。在滚珠批量处理过程中,为了避免相邻滚珠周围鞘层的相互重叠对注入均匀性造成不良影响,对滚珠在靶台上摆放的最小距离进行了数值计算,计算结果表明：在电压

1602强激光与粒子束　　　　　　　　　　　　　第16卷

表2　理论计算结果和实验测量结果的对比

Table2　Comparisonofexperimentalmeasurementsandtheoreticalpredictionsofsheathexpanding

distancefromtoppointoftheball/cm

simulativevoltage/kV

experimentalvoltage/kV3.04.504.624.03.503.505.02.582.608.01.101.20

4　结　论

　　二维PIC模型模拟结果表明,对轴承滚珠进行PIII改性处理时,对于静止状态的滚珠注入剂量均匀性较差,引入旋转靶台可以有效地提高注入均匀性。在对滚珠进行批量处理时,相邻滚珠之间的距离必须大于滚珠周围鞘层的两倍。实验研究表明,测量结果和模拟计算结果吻合较好。

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Numericalsimulationofbearingballsintheplasma

immersionionimplantationprocess

YUYong2hao,　WANGLang2ping,　WANGXiao2feng,　TANGBao2yin,

　GANKong2yin,　LIUHong2xi,　WANGYu2hang,　WANGSon2yan

(StateKeyLaboratoryofAdvancedWeldingProductionandTechnology,

HarbinInstituteofTechnology,Harbin150001,China)

　　Abstract:　Theprocessofbearingballsintheplasmaimmersionionimplantation(PIII)wassimulatedusinga22dimensionalparti2cle2in2cell(PIC)model.Thedistributionsofnormalizedpotentialanddosewerestudied.Inordertoavoidoverlapofsheathsbetweendifferentballsinbatchprocess,theminimumdistancebetweentwoneighboringballswascalculated.Whenthevoltageis-40kV,

μs,theminimumdistancebetweentwoballsshouldbe34.18cm.Inaddition,plasmadensityis4.8×109cm-3andpulsewidthis10

thedosedistributionalongthecircumferenceoftheballisnon2uniform.Consequently,arevolvingsubstratewasusedtoimprovetheuni2formity.Furthermore,toevaluatethemodel,theexpansionprocessofsheathwasmeasuredusingaLangmuirprobe.Experimentalre2sultsagreewiththecalculatedvalue,andthemaximumrelativeerrorislessthan8.4%.

　　Keywords:　Plasmaimmersionionimplantation;　Numericalsimulationofsheathdynamics;　Implantationdoseuniformity