Structural elements of shallow thermal donors formed in nitrogen-gas-doped silicon crystals

It has been reported that shallow thermal donors (STDs) are formed in oxygen-rich silicon (Si) crystals preannealed in nitrogen gas (N-gas-doped) and also in hydro-en-doped (H-doped) oxygen-rich Si crystals. The STDs formed ill these crystals exhibit very similar electronic Structures. Experiments using far-infrared optical absorption showed that several hydro-en-like STDs were formed at the same time and their energy levels in both the above-mentioned crystals were very similar. It has also been reported that the g-values Of the STDs formed in both the crystals were identical. Oil the basis of electron-nucleus double resonance results, it has been strongly Suggested that a hydrogen impurity is incorporated as a Structural element of the STDs formed in the H-doped Si crystals. However, the Origin of the STDs that are formed in N-gas-doped Si Crystals is Still Unclear. To clarify this point, hydrogen detection in N-gas-doped Si Was Conducted and the annealing behaviors of STDs in N-gas-doped Si and H-doped Si were compared by electron spin resonance and far-infrared optical absorption measurement. It was Concluded that the origin of the STDs formed in N-gas-doped Si crystals is not related to the hydrogen impurity.