HYDROGEN-ANNEALING INDUCED POSITIVE CHARGE IN BURIED OXIDES - CORRESPONDENCE BETWEEN ESR AND C-V RESULTS

The positive charge, introduced into the buried oxide (BOX) layer of s eparation by implanted oxygen (SIMOX) material by annealing in hydroge n in the temperature range 450-700 degrees C, has been measured by a n ovel charge sensing technique based on electron spin resonance (ESR). Standard capacitance-voltage (C-V) analysis has been used as a crucial test for this ESR method, yielding excellent agreement between the ar eal BOX-charge densities as obtained by the two techniques. Photoinjec tion of charges and optical excitation experiments have been performed subsequent to the hydrogen charging treatment to obtain additional in formation on location and stability of the hydrogen-induced positive c enters. The charge injection experiments revealed that these centers a re very stable (even electron injection does not affect them despite t heir Coulombic attractive potential). Generally, the charge injection and optical excitation data, together with the results from both ESR a nd C-V etchback experiments, show that the BOX charge is located very near the two Si/BOX interfaces (within a layer of less than or equal t o 20 nm).