Electrically active radiation-induced defects in Czochralski-grown Si with low carbon content

Electrically active defects induced by electron irradiation in Czochralski (Cz)grown Si crystals with low carbon content (N-C <= 2 x 10(15) cm(-3)) have been studied by means of Hall effect measurements, deep level transient spectroscopy (DLTS) and high-resolution Laplace DLTS (LDLTS). It has been found that in n-type carbon-lean Cz-Si irradiated at room temperature a centre with an acceptor level at E-c - 0.11 eV (E-0.11) is one of the dominant radiation-induced defects. This centre is not observed after irradiation in Cz-Si crystals with NC > 10(16) cm(-3). The E-0.11 trap anneals out in the temperature range 100-130 degrees C with the activation energy 1.35 eV. In p-type Cz-Si crystals with low carbon content and boron (NB 2 x 10(14) cm(-3)) one of the dominant radiation-induced defects has been found to be a bistable centre with an energy level at E-v +0.255 eV (H-0.255). It has been inferred from the analysis of temperature dependences of electron occupancy of this level that it is the E(0/++) level of a defect with negative Hubbard correlation energy (negative U). The activation energy for hole emission from the doubly positively charged state of the H0.255 Centre has been determined as 0.358 eV from LDLTS measurements. It is argued that the E-0.11 and H-0.255 energy levels are related to a complex incorporating an oxygen dimer and Si self-interstitial.