Retrograde well is a new process for ULSI fabrication. High energy ion implantation has been used for retrograde well formation. In this paper the forming condition for retrograde well using high energy ion implantation is compared with that for conventional well. TW signals for retrograde p-,n-well($900^{circ}C$),after annealing are similar trends to those of conventional ones($1150^{circ}C$), however the signals for RTA have the highest value because of small thermal budget. Junction depths of retrograde well are varied from about 1.2 to $3.0{mu}m$ as for conventional well. The peak concentrations of retrograde well, however, are about 10 times higher in values than those of conventional ones so that they can be used as any types of potential barriers or gettering sites. The critical dose for phosphorus implantation in our experiments is between $3 imes10^{13} and 1 imes10^{14}/cm^2$. Under the above critical dose, there are many secondary defects near projected range such as dislocation lines and dislocation loops.