RADIATION-INDUCED DEGRADATION OF SI/SIO2 STRUCTURES AND THE NATURE OF DEFECTS

Differently prepared specimen show after different irradiation treatments (VUV or X-ray) the same character of interface state distribution and hole trap related oxide charge. The dominating interface state generation process is considered to be a breaking-up of Si-H bonds. Centres of both back bond configurations (Si3) = Si-H and (Si2O) = Si-H are involved, where the latter has stronger irradiation effects due to the lower bond energy. The radiation induced oxide charge consists of positively charged hole traps with a trap energy of E(t) = 6.3 eV. They are dischargeable by electron tunneling from the adjacent Si. This leads to a dynamical trapping behaviour dependent only on the hole current density. Our results confirm that the paramagnetic E'-centre constitutes the positively charged hole trap.