DEFECTS INDUCED BY DEEP PREAMORPHIZATION AND THEIR EFFECTS ON METAL-OXIDE-SEMICONDUCTOR DEVICE CHARACTERISTICS

The crystalline quality of deeply preamorphized and recrystallized Si layers has been studied for application to channel preamorphization. D eep preamorphization by 300 keV Si2+ and 150 keV Si+ implantations ind uces spanning dislocations in addition to end-of-range defects, while relatively shallow preamorphization by 150 keV Si+ implantation result s only in the generation of end-of-range defects. Deep preamorphizatio n causes large leakage currents in junction diodes because of spanning dislocation generation. It does not degrade gate oxide quality as lon g as amorphous lavers that extend to the sur-face are created. Relativ ely shallow (similar to 0.3 mu m) preamorphization does not degrade th e leakage characteristics of junction diodes if the end-of-range defec ts are not located in the depletion lavers. It is therefore effective to adopt both relativley shallow preamorphization and shallow source/d rain junctions. Otherwise, deep preamorphization by low-temperature Si implantation is effective.