Search

Silicon-on-insulating multi-layer (SOIM) materials were fabricated by co-implantation of oxygen and nitrogen ions with different energies and doses. The multilayer microstructure was investigated by cross-sectional transmission electron microscopy. P-channel metal–oxide–semiconductor (PMOS) transistors and metal–semiconductor–insulator–semiconductor (MSIS) capacitors were produced by these materials. After the irradiated total dose reaches 3×105 rad (Si), the threshold voltage of the SOIM-based PMOS transistor only shifts 0.07 V, while thin silicon-on-insulating buried-oxide SIMOX-based PMOS transistors have a shift of 1.2 V, where SIMOX represents the separated by implanted oxygen. The difference of capacitance of the SOIM-based MSIS capacitors before and after irradiation is less than that of the thin-box SIMOX-based MSIS capacitor. The results suggest that the SOIM materials have a more remarkable irradiation tolerance of total dose effect, compared to the thin-buried-oxide SIMOX materials.

Total ionizing dose effects of Si+ ion implanted thermal oxides are studied by 10 keV x-ray irradiation. Photoluminescence (PL) method is engaged to investigate nanostructures of samples. Ar+ implanted samples are also studied by the same way to provide a comparison. The results show that Si+ implantation following with high temperature annealing can significantly reduce the radiation induced flatband shift, which is caused by net positive charge accumulation in oxides. This reduction is attributed to the formation of Si nanoscale structures. Ar+ implantation is also found to reduce the radiation induced flatband shift, while it is different that the reduction with Si+ implantation shows little dependence on implant dose of Ar+ ions. This is explained by possible increase of recombination centres.

Effects of techniques of implanting nitrogen into buried oxide on the characteristics of the partially depleted silicon-on-insulator (SOI) p-channel metal-oxide-semiconductor field-effect transistors (PMOSFETs) have been studied with three different nitrogen implantation doses, 8 x 10(15), 2 x 10(16), and 1 x 10(17) cm(-2). The experimental results show that this technology can affect the threshold voltage, channel hole mobility and output characteristics of the partially depleted SOI PMOSFETs fabricated with the given material and process. For each type of the partially depleted SOI PMOSFET with nitrided buried oxide, the absolute value of the average threshold voltage increases due to the nitrogen implantation. At the same time, the average channel hole mobility decreases because of the nitrogen implantation. In particular, with the high nitrogen implantation doses, the output characteristic curves of the tested transistors present a distinct kink effect, which normally exists in the characteristic output curves of only partially depleted SOI NMOSFETs.