We carried out sub-Kelvin ultrasonic measurements for observation of vacancies in crystalline silicon. The longitudinal elastic constants of non-doped and B-doped floating zone (FZ) silicon crystals in commercial base revealed low-temperature elastic softening below 20 K. The applied magnetic fields turns the softening of the B-doped FZ silicon to a temperature-independent behavior, while the fields up to 16 T at base temperature 20 mK make no effect on the softening of the non-doped FZ silicon. This result means that the vacancy accompanying the non-magnetic charge state V0 in the non-doped silicon and the magnetic V+ in the B-doped silicon is responsible for the low-temperature softening through the Jahn-Teller effect. The direct observation of the vacancy using the sub-Kelvin ultrasonic measurements advances point defects controlling in silicon wafers and semiconductor devices.
|ジャーナル||Materials Science and Engineering B: Solid-State Materials for Advanced Technology|
|号||2-3 SPEC. ISS.|
|出版ステータス||Published - 2006 10月 15|
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