Phase transition of high-dielectric insulating films studied by extremely asymmetric X-ray diffraction and X-ray photoelectron spectroscopy

用同步辐射掠入射X射线衍射仪研究了HfO_2和HfAlO_x薄膜的晶化过程。用原子层沉积(ALD)方法在SiO_2化学界面层上生长了HfO_2和HfAl_1O_x薄膜。X射线衍射图表明，沉积的HfO_2薄膜不仅有单斜晶相，也有正交相或四方相。随退火温度的升高，三方相或四方相逐渐减少并消失。HfAlOx薄膜在900℃下进行了晶化处理。晶体相为CaF_2型立方相。用极不对称X射线衍射仪研究了沉积后退火对HfO_2/Si界面的影响。对比样品退火前的摇摆曲线和退火后样品的摇摆曲线，发现在后沉积退火过程中，在HfO2层与衬底的界面处形成了密度为3g/cm3的界面层。…此外，沉积样品的摇摆曲线积分强度的波长依赖性随观测位置的不同而波动。这种涨落被退火抑制了。根据这些结果，我们得出结论，引入到衬底中的应变通过退火变得均匀。此外，通过曲线拟合对应变的定量估计揭示了HfO_2层下压应变的存在。我们研究了采用逐层沉积和退火法(LL-D&A)在不同的退火条件下制备的HfA10x(N)/SiO_2/Si薄膜。在此期间，在NH_3气氛中进行了不同温度的原位热处理。此外，还对部分样品进行了沉积后退火(PDA)。用应变敏感X射线衍射法测量了界面晶格应变，用X射线光电子能谱(XPS)测量了Al原子附近的局域介电常数。通过测量掠入射条件下Si(001)衬底上Si113反射的X射线摇摆曲线来观察应变场。研究发现，在没有PDA的情况下，对于较高的原位退火温度，引入了压缩应变，局部介电常数变得较低。对于具有PDA的样品，不同的原位退火温度对晶格应变和局域介电常数的影响不大。较少

We have studied the crystallization process of HfO_2 and HfAlOx films using grazing incidence X-ray diffraction (GIXRD) with synchrotron radiation. The HfO_2 and HfA1Ox films were grown by atomic layer deposition (ALD) on a chemical Si02 interfacial layer. X-ray diffraction (XRD) patterns of the HfO_2 film as-deposited contain not only the monoclinic phase but also the orthorhombic or tetragonal phase. With increasing annealing temperature, the orthorhombic or tetragonal phase decreases and disappears. The HfAlOx film crystallized after annealing at 900 ℃. The crystallographic phase was the cubic phase of CaF_2 type.We studied the effect of post-deposition annealing on a HfO_2/Si interface of by extremely asymmetric X-ray diffraction. Comparing the rocking curves before annealing the sample with those of the annealed sample, it is found that an interfacial layer with a density of 3 g/cm^3 grows at the interface between the HfO_2 layer and the substrate during post-deposition annealing. … More The wavelength dependency of the integrated intensities of the rocking curve for the as-deposited sample fluctuated with the observation position. This fluctuation was suppressed by annealing. From these results we concluded that the strain introduced into the substrate becomes homogeneous by annealing. Moreover, a quantitative estimation of the strain by curve fitting reveals the existence of compressive strain under the HfO_2 layer.We studied HfA10x(N)/SiO_2/Si films which were fabricated by the layer-by-layer deposition and annealing (LL-D＆A) method with different annealing conditions. In this time, in-situ annealing was performed at various temperatures in a NH_3 ambient. In addition, post-deposition annealing (PDA) was performed for some samples. For each sample, the interfacial lattice strain was evaluated using strain-sensitive X-ray diffraction and the local dielectric constant near the Al atoms was measured by X-ray photoelectron spectroscopy (XPS). Observation of the strain field was done by measuring the X-ray rocking curve of the Si 113 reflection of the Si (001) substrate under grazing incidence conditions. It was found that in the case of the samples without PDA, for higher in-situ annealing temperatures compressive strain is introduced and the local dielectric constant becomes lower. For the samples with PDA, the differences of the lattice strain and the local dielectric constant are small for different in-situ annealing temperatures. Less