We have developed a high-accuracy difference X-ray reflectivity (DXR) method using intense synchrotron radiation for the evaluation of ultrathin thermal oxides on Si(100). By carefully analyzing DXR data for gate oxides with thicknesses of 40 Å and 70 Å grown at 800° C to 1000° C, the existence of a dense ( ∼2.4 g/cm3), thin (∼10 Å) layer at the S
i
O
2/S
i interface has been revealed. The thickness of the interfacial layer decreases with increasing oxidation temperature. Oxides grown in O3 or HCl/O2 have a thinner interfacial layer compared to those grown in O2.
We investigated the effects of fluorine on boron diffusion in thin silicon oxides used for metal-oxide-semiconductor structures, including silicon dioxide and oxynitride. We used secondary ion mass spectroscopy to measure the boron penetration depth from p+-polycrystalline silicon to the silicon substrate through the silicon oxides for various fluorine doses. We compared experimental and simulated results and determined the boron diffusion coefficients in the silicon oxides. The diffusion coefficients have an Arrhenius relationship for each fluorine dose. The diffusion coefficients at a fluorine dose of 1×1016 cm−2 were 30 times larger than with no fluorine dose, and at a fluorine dose of 1×1015 cm−2, diffusion coefficients were 5 times larger. With oxynitride, fluorine has the same enhancing effect. With no fluorine, the diffusion coefficients were independent of oxide thickness. When fluorine is implanted into polycrystalline silicon, especially with a high dose, the diffusion coefficient is larger for thinner oxides because of the higher fluorine concentration.
Articles you may be interested inEffect of Al ion implantation on the adhesion of Al films to SiO2 substrates Cell design for in situ xray scattering studies of metal/solution interfaces under electrochemical control Rev.We have developed a high-precision difference-x-ray-reflectivity technique using intense synchrotron radiation and applied this to evaluate native oxides and ultrathin thermal oxides on Si͑100͒. We have successfully evaluated the density of native oxides. Native oxides formed by HCl and NH 4 OH solutions have a low density, in contrast to the oxides formed by H 2 SO 4 solution and UV/O 3 whose densities are close to those of thermal oxides. By carefully analyzing ultrathin thermally grown oxides with thicknesses of 40 and 70 Å grown at 800-1000°C, we have revealed the existence of a dense ͑ϳ2.4 g/cm 3 ͒, thin ͑ϳ10 Å͒ layer at the SiO 2 /Si interface. Oxides grown in O 3 or HCl/O 2 have a thinner interfacial layer compared to those grown in O 2 . We have evaluated the effects of ambient and temperature at oxidation on the interfacial layer and the SiO 2 layer.
Articles you may be interested inThermal decomposition behavior of the HfO 2 / SiO 2 / Si system J. Appl. Phys. 94, 928 (2003); 10.1063/1.1578525 Characterization of annealing effects of low temperature chemical vapor deposition oxide films as application of 4H-SiC metal-oxide-semiconductor devices Process sensing and metrology in gate oxide growth by rapid thermal chemical vapor deposition from SiH 4 and N 2 O
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