Time-resolved photoluminescence analysis of multidose Si-ion-implanted SiO2

Abstract

The continuous-wave/time-resolved photoluminescence (CWPL/TRPL) and capacitance - voltage (C-V) analysis of multirecipe silicon-ion-implanted SiO2 (SiO2:Si+) are demonstrated to study the lifetime evolution of three radiative defects with luminescent peaks at 415, 455, and 520 nm, which are identified as the weak oxygen bonding (O-O) defects, neutral oxygen vacancy (NOV), and precursors of nanocrystallite Si(E-delta') defects, respectively. The TRPL analysis reveals that the concentrations of weak oxygen bonding and NOV defects with lifetimes of 12 - 16 ns in as-implanted SiO2:Si+ are 3-4 x 10(17) cm(-3), agreeing well with those determined using C-V analysis. The NOV and weak oxygen-bonding defects reach their maximum densities and the shortest emission lifetimes of 7.0 x 10(18) cm(-3) and 3.6 - 7.2 ns, respectively, after annealing for 1.5 - 3 h. These results support the dissociation of SiO2 matrix during a Si-implanting process with a reaction of O-3 equivalent to Si-O-Si equivalent to O-3 -> O-3 equivalent to Si-Si equivalent to O-3 + O-interstitial -> NOV + (1/2) O-O, which is the origin of the strong blue-green CWPL observed in the SiO2:Si+. The regrowth of SiO2 matrix after long-term annealing is also confirmed by the significant reduction of NOV and weak oxygen bonding defects. In contrast, the concentration of the E-delta' center reveals a slowly increasing trend due to the less pronounced precipitation of nanocrystallite Si in SiO2:Si+ during the annealing process. (c) 2005 The Electrochemical Society.