Retardation in the chemical-mechanical polish of the boron-doped polysilicon and silicon

;This letter reports on the chemical-mechanical polishing (CMP) of boron do ped polysilicon and silicon. Successive polishing was carried out to invest igate how the removal rate correlates to the boron concentration as a funct ion of depth in the polysilicon and crystalline silicon. It is found that t he removal of baron-doped samples is significantly retarded and strongly co rrelated with the doping concentration. To the author's knowledge, this wor k is the first report discussing the retardation effect of boron in the Si- CMP process, This effect is attributed to the activated dopant atoms which are conjectured to inhibit the hydrolysis reaction of Si-Si bonding in the alkaline aqueous solution. In our study, the retardation effect is evident for the boron concentration higher than 5 x 10(18) cm(-3). As a consequence , it may become an issue in CMP process for those layers of selected or com plemented doping.