Formation Mechanism of PPS as Antireflection Coating

(整期优先)网络出版时间:2005-01-11
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ThewholechemicaletchingprocessonaP-typepolycrystallinesiliconsubstratewithresistivity1-2Ω·cmisdescribed.Theformationmechanismofporouspolycrystallinesilicon(PPS)microstructurewasinvestigated.ThosehowtheinitialpitswereformedandanuniformmorphologyofPPSwasobtainedareexplained.Twotypesofetchingmechanismwerecharacterizedasdefectcontrolreactionanddiffusioncontrolreaction.ThemorphologyformedaftertheisotropicacidicsolutionetchingwithdifferentetchingtimeandHF/HNO3concentrationwascomparedwiththeeffectofthesameetchingprocessafteranisotropicalkalineetching.Thestudyshowedthatthethicknessofporouspolycrystallinesiliconlayerwithchemicalacidicetchingentirelydependedontheexistenceofvarioustypesofdefects.