Characteristics of Sol–Gel-Derived and Crystallized HfO2 Thin Films Dependent on Sol Solution
Characteristics of Sol–Gel-Derived and Crystallized HfO2 Thin Films Dependent on Sol Solution
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DOI：
10.1143/jjap.49.121502
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发表时间：
2010-12
影响因子：
1.5
通讯作者：
H. Shimizu;Dai Nemoto;M. Ikeda;T. Nishide
中科院分区：
文献类型：
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作者：
H. Shimizu;Dai Nemoto;M. Ikeda;T. Nishide
我们研究了溶胶-凝胶衍生的二氧化铪（HfO 2）薄膜在硅衬底上焙烧在空气中在350，450，550，和700 °C的30分钟使用甲酸（HCOOH）或硝酸（HNO 3）溶液作为催化剂。在低于450 °C下，两种膜都是非晶的并且约8-10 nm厚。发现在560 °C下在HCOOH溶胶中发生结晶成单斜结构（111）。在HNO 3溶胶中，在470 °C下结晶成单斜结构（111）和（111）。使用每种溶胶溶液的溶胶-凝胶衍生的HfO 2薄膜的程序升温脱附曲线被分成五个不同的H2O脱附组分，所述H2O脱附组分由HfO 2膜中的物理吸附的H2O、化学吸附的OH和/或Hf-OH键引起。在此基础上，提出了一个模型来解释H2O解吸机理。计算得到溶胶-凝胶法制备的HfO 2薄膜的介电常数（相对介电常数：ε HfO 2）为11，EOT为2.1 nm，有待进一步提高。作为先进的集成互补金属氧化物半导体（CMOS）器件中的替代栅极绝缘体，溶胶-凝胶衍生的HfO 2膜的非晶态对于两种溶胶溶液都是有希望的，如果可以实现H2O解吸并消除其他缺陷。
We investigated sol–gel-derived hafnium dioxide (HfO2) films on silicon substrates fired in air at 350, 450, 550, and 700 °C for 30 min using either formic acid (HCOOH) or nitric acid (HNO3) solutions as a catalyst. At less than 450 °C, both films are amorphous and approximately 8–10 nm thick. Crystallization into the monoclinic structure (111) was found to occur at 560 °C in the HCOOH sol. In the HNO3 sol, the crystallization into the monoclinic structures (111) and (111) occurs at 470 °C. The temperature-programmed desorption curves of the sol–gel-derived HfO2 thin films using each sol solution are separated into five distinct H2O desorption components caused by physically adsorbed H2O, chemically adsorbed OH, and/or Hf–OH bonds in the HfO2 film. On the basis of these components, a model is proposed to explain the H2O desorption mechanism. The dielectric constant (relative permittivity: εHfO2) of the sol–gel-derived HfO2 film was calculated to be 11 and the EOT was estimated to be 2.1 nm, which need to be improved. As an alternative gate insulator in advanced integrated complementary metal–oxide–semiconductor (CMOS) devices, the amorphous state of the sol–gel-derived HfO2 film is promising for both sol solutions, if H2O desorption can be accomplished and other defects eliminated.