Electrical characteristics of the interface between the top Si and buried oxide in ITOX-SIMOX wafers

Summary form only given. High-quality ITOX-SIMOX (internal thermal oxidation-SIMOX) wafers (Nakashima et al, 1994) have been used for the fabrication of 0.25 /spl mu/m fully-depleted CMOS-SIMOX LSIs (Ino et al, 1996). In fully-depleted devices, device performance strongly depends on the quality of the interface between the top Si and the buried oxide (top Si-buried oxide interface) as well as that of the gate oxide-top Si interface. However, there are few reports on the electrical characteristics of the top Si-buried oxide interface. Accordingly, we fabricated a buried MOS diode, which has a P/sup +/ gate beneath the buried oxide, in ITOX-SIMOX wafers and investigated the electrical characteristics of the interface. The obtained results reveal that the fixed charge density Q/sub f//q and the interface trap density D/sub it/ are extremely small, and are comparable to those of thermal oxide. These results indicate that the ITOX-SIMOX wafer has a high quality top Si-buried oxide interface, and the reduced pinhole density and high quality interface of ITOX-SIMOX wafers are useful for the fabrication of fully-depleted CMOS-SIMOX LSIs.