Adhesion and leakage current characteristics of selective CVD tungsten films on the silicon substrate

ABSTRACT- In this study we investigated the effects of SF, and CF, plasma p~etreatments on the adhesion and junction leakage characteristics of the selective CVD W films by SiH, reduction of WF, on the Si subsbate. The SF, plasma ptetreatment performed in situ prior to W deposition to remove the polymer films in contact holes results in enhancement of the adhesion of W films to the Si substrate but degradation of junction leakages due to veltical and lateral S i consumptions. The CF, plasma prmeatment perbrmed as the last step of the reactive ion etching for contact window opening produced the WISi contacts of good adhesion, low contact resistances and low junction leakages for thin W films, while it produced the W/Si contacts of poor adhesion and high contact resistances for thick W films. The selective CVD W films deposited by the three step pmcess of SiH, reduction / in situ annealing / SiH, reduction was found to have both good adhesion and low junction leakage characteristics.