Hartmut Runge

Spatial position of deep levels near the Si—SiO 2 interface of ion implanted MOS structures

Measurements of the threshold voltage shift of MOS transistors in dependence on the implantation energy are correlated with calculations of the number of ions implanted in a small Si-layer beneath the gate oxide. The thickness of this layer and the number of deep levels per implanted ion is determined. The energy level ETof the implanted35Cl+in the silicon is approximately 0.85 eV below the conduction band.

Threshold voltage shift ofp-channel MOS-transistors by implantation of donors

If the number of electrically activated donors after implantation and annealing is (10 min at 500° C) determined by Hall-measurements and if these values are used to compute the threshold voltage shift of P+ and As+-implantedp-channel MOS-transistors, calculation and experiment do not agree. The difference can be explained by considering that deep levels are created by ion implantation.

Threshold Voltage Shift of Mos-Transistors by Ion Implantation of B, Al, Ga, P and As

Shifting the threshold voltage of p-channel MOS transistors by implanting B+ ions has become a standard process for many semiconductor device manufacturers. Nevertheless problems still exist, as will be shown in this paper.

Method of fast change of dopants for ion implantation.

Abstract A method to reduce the time to change dopants in ion implantation systems is described. The source is fed by a suitable mixture of dopant compounds and the desired dopant is selected by mass separation. The down time thus reduces to less than one minute. The main ion optical parameters of the system remain unchanged.

The influence of deep levels on the temperature coefficient of ion-implanted resistive layers in silicon

Ion-implanted high ohmic resistors may exhibit a low temperature coefficient, if the annealing after implantation is not complete. This effect is explained by deep energy levels. Experimental results are presented for B+- and Al+-implanted resistors.