Stabilization of charge at the interface between the buried insulator and silicon in silicon-on-insulator structures

The effect of additional implantation of hydrogen ions into the region of the interface between the split-off silicon layer and the buried insulator in silicon-on-insulator structures and subsequent high-temperature annealing on the parameters of the structures and their radiation resistance is studied. This modification of silicon-on-insulator structures gives rise to the following effects. The mobile charge present in the oxide of the initial structures becomes immobilized, which stabilizes the characteristics of silicon-on-insulator structures and simultaneously increases the fixed charge near the boundary with the split-off silicon layer. Furthermore, additional traps are introduced into the oxide; these are predominantly electron traps that accumulate negative charge during irradiation. As a result, the charge in the oxide of silicon-on-insulator structures is decreased somewhat at the initial stage of irradiation but then remains nearly unchanged up to doses of 10⁷ rad. Conventional accumulation of positive charge occurs at the second boundary of the structure and is typical also of initial (unmodified) silicon-on-insulator structures.