Radiation-induced charge effects in buried oxides with different processing treatments

The authors characterize the radiation-induced charge trapping and transport properties of the buried-oxide (BOX) layer using the photocurrent response technique and capacitance-voltage shift measurements for a variety of silicon-on-insulator (SOI) materials. They observe dramatic differences as a result of different BOX processing conditions. The radiation response of the SOI materials as a whole is shown to be consistent with the basic properties of the material(s) contained in the BOX layer. In comparison to standard separation by implantation of oxygen (SIMOX) materials, SIMOX materials receiving a supplemental oxygen implant and low-temperature anneal produce large normalized photocurrent values, indicating that both radiation-generated charge carriers move through the BOX. Of the materials examined, the bond-and-etch-back SOI (BESOI) material containing a silicon nitride layer produced the lowest normalized photocurrents, heavy trapping of both carriers. By comparison, BESOI with thermal oxide layers traps neither carrier in the oxide bulk. The authors suggest that results of this study should be considered in the design of radiation-hardened components and when considering processing variations. >