Nicholas H. Tripsas

Plasma Model for Charging Damage

The mechanism responsible for charging damage to integrated circuit device insulators is treated as a plasma phenomenon, in which the beam/plasma drives potential differences on the process surface. J−V data obtained with the CHARM2 diagnostic in a high current implanter (flood OFF) are fit with a plasma probe model. The fit indicates plasma buildup over the wafer surface. A cold plasma flood is suggested as a means of limiting potential differences during ion implantation.

Surface charge control during high-current ion implantation: characterization with CHARM-2 sensors

Abstract Studies of the charging effects during implantation with 9200 and 9500 tools using EEPROM-based sensors, CHARM-2, are reported for 60 keV As beams.

Modification of time dependence in thermal wave signal from ion implanted wafers

Abstract The thermal wave signal from ion implanted silicon wafers exhibits gradual change as a function of time after implant. This change in thermal wave signal can affect the long term repeatability of measurements made on implant monitors. This paper describes a method for reducing, and in many cases eliminating, the time dependence of the thermal wave signal. Wafers implanted with B+, P+, and As+ at doses ranging from 1011 to 1014 ions/cm2 and energies from 60–100 keV were subjected to l temperature anneals for varying times. The decay factor was studied as a function of anneal temperature and time. The effect of exposure of the wafers to UV radiation is also discussed.