Process characterization of law-dose, threshold-voltage adjust channel implants using mercury-probe capacitance-voltage measurements

The distinct need exists, now, for the capability to accurately and quickly characterize the quality of implants used in threshold-voltage adjusts. In this article we address, in detail, highly sensitive dose and energy monitoring of low-dose implants using a nondestructive, soft-contact mercury-probe capacitance-voltage technique. Currently, wafers are monitored using a wide variety of techniques that work on either a pass-fail basis, or using costly destructive techniques. These techniques lack the sensitivity that is critical for process control of implant and annealing conditions. Data are presented in the form of electrically active carrier density profiles. Detailed information such as partial implant dose, peak carrier density, range, and substrate concentration is determined. These values are enhanced further by the ability to look at uniformity over the entire wafer. From the data collected, rapid and detailed feedback about the condition of the implanter and the annealer(s) is obtained. Quality control and statistical process control of the technique will be analyzed in great detail. (C) 2000 American Vacuum Society. [S0734-211X(00)06601-4].