Reuben E. Joynson

Eliminating threshold losses in MOS circuits by bootstrapping using varactor coupling

Threshold losses reduce speed and increase power consumption of MOS digital circuits. A method to eliminate these losses is described. This is accomplished by the application of bootstrapping, in which a temporarily isolated circuit node is capacitatively coupled to the input voltage. The advantages of a MOS varactor element and its use for the coupling capacitor are described.

I‐V characteristics of MOS capacitors with polycrystalline silicon field plates

The I‐V characteristics of MOS capacitors utilizing polycrystalline p‐type silicon field plates were investigated. It was found that sizable current flow is observable in both directions under pulsed dc conditions at voltages much below those at which current flows under applied dc. This suggests that the polycrystalline silicon film can be driven into avalanche and thus inject electrons into the oxide as well as the single‐crystal Si wafer. Charge trapping during passage of avalanche injected currents was observed to occur principally at the silicon/oxide interfaces. The rate of trapping depended strongly on the boron content of the oxide.

Channel Shortening in MOS Transistors during Junction Walk‐Out

The walk‐out of the breakdown voltage of the junctions of p‐channel MOS transistors was found to be accompanied by an increase in the transconductance. An explanation for this relationship is offered here in terms of electron injection into the gate oxide near the junctions, and subsequent trapping there. The rate of junction walk‐out depends not only on the total injected negative charge, but also on the value of the injection current itself, increasing at higher injection currents. The ratio of the injection current to the total junction current is found to decrease with increasing breakdown voltage.

Electron trapping in thin SiO2 films due to avalanche currents

Abstract The avalanche breakdown phenomenon in silicon results in the injection of charge into silicon dioxide, where it may be partly trapped. Experimental results on the dependence of electron trapping in silicon dioxide on total dose and dose rate (current density) are presented for avalanching MOS drain junctions and capacitors.

Eliminating threshold losses in MOS circuits by varactor bootstrapping

Threshold losses reduce speed and increase power consumption in MOS digital circuits. A method using a MOS varactor element to eliminate the effects of those losses is described.

Avalanche Breakdown in Polycrystalline Silicon Films

Electrons can flow from the field plate of a silicon gate MOS, through the gate oxide, to the contacts or the channel, if the field plate is brought into avalanche. This leads to shifts in the transistor threshold voltage, and premature discharge of floating nodes. The characteristics of p-type polycrystalline silicon films in MOS avalanche have been examined. Avalanche injected electron currents in the gate oxide up to 1 mA/cm2 have been measured at 500 KHz. Trapping of electrons occurs at a distance of 100 A from the oxide interface, and appears to depend strongly on the boron content of the gate oxide.