Kato Kazuhiro, Omoto Hideo, Yonekura Masaaki
Glass Research Center, Central Glass Co. Ltd., 1510 Ohkuchi-Cho, Matsusaka-City, Mie pref. 515-0001, Japan.
J Nanosci Nanotechnol. 2012 Dec;12(12):9183-6. doi: 10.1166/jnn.2012.6757.
The annealing effects on the properties of ITO and pure In2O3 thin films have been investigated. The thin films were deposited with various O2 flow ratios to total gas flow by pulsed dc magnetron sputtering. The post-deposition annealing of the thin films was carried out for 30 minutes at various temperatures ranging up to 500 degrees C in air. It was found through the comparison of the carrier density of ITO and In2O3 thin films that the carrier electrons of the ITO thin films came from both of the dopant Sn and oxygen vacancies under the annealing less than 400 degrees C. Therefore, the ITO thin films deposited with lower O2 flow ratio exhibited higher carrier density due to many oxygen vacancies; in consequence, they exhibited lower resistivity at the annealing up to 400 degrees C. On the other hand, the carrier density of ITO thin films was almost identical regardless of O2 flow ratio when they were annealed at 500 degrees C. This fact indicates that most carrier electrons of the ITO thin films were brought by the dopant Sn at the annealing temperature of 500 degrees C. However, the ITO thin films deposited with lower O2 flow ratio exhibited higher Hall mobility; as a result, they showed lower resistivity at the annealing of 500 degrees C. Atomic force microscope, X-ray diffraction and X-ray reflectivity measurements revealed that the ITO thin films deposited with lowe O2 flow ratio exhibited dense structure even after they were annealed at 500 degrees C. Hence, the carrier electrons of the dense ITO thin films deposited with low O2 flow ratio can conduct better, as a result, the ITO thin films exhibited high Hall mobility and low resistivity.
研究了退火对ITO和纯In2O3薄膜性能的影响。通过脉冲直流磁控溅射，以不同的O2流量与总气体流量之比沉积薄膜。在空气中，将薄膜在高达500℃的不同温度下进行30分钟的沉积后退火。通过比较ITO和In2O3薄膜的载流子密度发现，在低于400℃的退火温度下，ITO薄膜的载流子电子来自掺杂剂Sn和氧空位。因此，由于存在许多氧空位，以较低O2流量比沉积的ITO薄膜表现出更高的载流子密度；结果，在高达400℃的退火温度下，它们表现出更低的电阻率。另一方面，当ITO薄膜在500℃退火时，无论O2流量比如何，其载流子密度几乎相同。这一事实表明，在500℃的退火温度下，ITO薄膜的大多数载流子电子是由掺杂剂Sn提供的。然而，以较低O2流量比沉积的ITO薄膜表现出更高的霍尔迁移率；结果，在500℃退火时，它们表现出更低的电阻率。原子力显微镜、X射线衍射和X射线反射率测量表明，即使在500℃退火后，以较低O2流量比沉积的ITO薄膜仍表现出致密的结构。因此，以低O2流量比沉积的致密ITO薄膜中的载流子电子传导性更好，结果，ITO薄膜表现出高霍尔迁移率和低电阻率。
