Photoconduction measurements of the charge trapping and transport in bond-and-etch-back buried oxides

The charge trapping and transport characteristics of bond-and-etchback buried oxides (BESOI) were investigated using a photoconduction current technique and total dose capacitance-voltage shift measurements. Results are compared with results previously obtained on standard SIMOX (separation by implantation of oxygen) materials. The photocurrent experiment was also performed on thermally grown oxides with an oxide layer similar in thickness to the BESOI and SIMOX material used in this study. Measurements were performed on the thermal oxides as a method of calibration for both the experimental and analytical methods that are applied to the photoconduction current technique. Large normalized photoconduction currents and large postirradiation midgap voltage shifts in the BESOI material were measured. Taken together, these results indicate that most of the electrons and the holes move through the BESOI oxide and significant fractions of the holes are trapped at the interfaces. These radiation response characteristics are also typical of non-radiation-hardened thermal oxides, and this leads to the further conclusion that techniques used to successfully harden thermal oxides may also be successful when applied to BESOI material