6.152J3.155J Under what conditions will Si melt crystallize? 6.12J/3.155J Microelectronic processing Liquid Si high s high H Crvstal Si △H=H(T)-H(r)<0 △G=△-As TAS must have smaller magnitude than 4/ for solidification: this defines solidification temp. N。v.26,2003 Note the relatively large solid solubility of As in Si 6.12J/3. 155J Microelectronic processing Atomic Portent Arsenic then decreases Arsenic solubility Whereas increases with T s As +SiA Nov.26,20036.152J/3.155J 3 5 Nov.26 , 2003 6.12J / 3.155J Microelectronic processing Under what conditions will Si melt crystallize? T Tm Liquid Si T = Tm + T = Tm - Crystal Si high S high H low S low H For solidification: DS = S T- ( )final - S T+ ( )initial < 0 DH = H T- ( ) - H T + ( ) < 0 DG = DH - TmDS < 0 > 0 TDS must have smaller magnitude than DH for solidification; this defines solidification temp. 6 Nov.26 , 2003 6.12J / 3.155J Microelectronic processing Note the relatively large solid solubility of As in Si Whereas this field is As + SiAs2 Arsenic solubility in Si increases with T ….then decreases on approaching Tmelt