Characteristics of buried-channel pMOS devices with shallow counter-doped layers fabricated using channel preamorphization

Abstract

Channel preamorphization, which is a technique used for shallow boron counter doping of pMOSFETs to suppress short-channel effects, improves gate oxide quality in MOS capacitors with the field-edge structure. This indicates that the source of gate oxide quality degradation is located near the field oxide edge, and is eliminated in channel preamorphization process by the gettering effects of defects induced near the original amorphous/crystalline interface. The leakage current of junction diodes, on the other hand, is increased by channel preamorphization. The leakage current increases because the defects near the original amorphous/crystalline interface act as generation centers in the depletion layers. This problem will be overcome by increasing the preamorphization depth. Hot carrier immunity of pMOSFETs is improved by channel preamorphization, especially in short-channel devices.