Structural and electrical characterization of low-dose low-energy SIMOX materials

Abstract

The effects of implantation dose, energy, and annealing conditions on the microstructure and the formation and evolution of defects in the low-dose, low-energy SIMOX materials were investigated using transmission electron microscopy (TEM), scanning electron microscopy, scanning electron microscopy (SEM), optical microscopy secondary ion mass spectroscopy (SIMS), and Rutherford backscattering spectrometry (RBS). The quality of top Si layer and buried oxide layer (BOX) was also characterized with the electrical measurements. From the structural characterization of 100 keV implanted samples, it was found that the optimum dose window to form a continuous BOX layer after annealing was 3.0 to 3.5 x 10¹⁷ O⁺/cm². In addition, the formation mechanisms of dislocations and stacking faults in SIMOX materials were also proposed. The Hg-based pseudo-MOSFET technique was a very effective in-situ technique to evaluate the electrical quality of low-dose low-energy SIMOX. Based on the comparisons of device parameters of low-dose low-energy SIMOX and commercial SIMOX samples, we found that the quality of top Si layer of SIMOX sample prepared at 100 keV with a dose of 3.5 x 10¹⁷ O⁺/cm² was excellent. However, the interface properties (interfacial trap density) needed to be improved. The dielectric quality of low-dose low-energy SIMOX evaluated by breakdown voltage measurements showed a strong dependency on the microstructure of samples.