High quality r.f. sputtered metal oxides (Ta2O5, HfO2 and their properties after annealing
High quality r.f. sputtered metal oxides (Ta2O5, HfO2 and their properties after annealing
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DOI：
10.1016/j.tsf.2003.07.013
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发表时间：
2004-01-30
期刊：
影响因子：
2.1
通讯作者：
Pechstein, I
中科院分区：
文献类型：
--
作者：
Grüger, H;Kunath, C;Pechstein, I
过渡金属氧化物的薄膜具有许多应用，如场效应晶体管（FET）和传感器中的栅极介电常数、电容器的高介电常数材料或光子应用的保护性透明涂层。重要的是良好的电学、光学和机械性能以及高化学惰性。自CMOS生产开始以来，氧化硅一直是标准材料。五氧化二钽已被研究多年。在这个领域，相当新的候选者是氧化铪。除了良好的性能外，所选材料还必须能够以可接受的速率提供可再现的均匀沉积。材料特性应该是可调节的，例如通过热退火，但在长期基础上不得改变。Ta_2O_5和HfO_2是用射频沉积法制备的。在Ar/O-2混合气体中溅射高纯靶。由于计划的传感器应用，沉积了150 nm的厚度。整个150 mm晶片上的总厚度变化（TTV）低于+/-6%。在沉积之后，用不同的方法对层进行退火。机械应力可以通过退火制度来调节。化学惰性随退火温度的升高而增加。所有层都是绝缘和透明的。特别是在950 ℃退火的HfO2显示出有利的结果：层是具有细晶粒结构的结晶，光滑，致密，并且非常好地耐受NaOH和HF。经验证，这些材料将适用于所需的应用，特别是与恶劣环境接触的应用。(C)2003 Elsevier B.V.保留所有权利。
Thin films of transition metal oxides have many applications like gate dielectrics in field effect transistors (FETs) and sensors, high-epsilon materials for capacitors or protective transparent coatings for photonic applications. Important are favorable electrical, optical and mechanical properties as well as high chemical inertness. Silicon oxide has been a standard material since the beginning of CMOS production. Tantalum pentoxide has been investigated for some years. Quite a new candidate in this area is hafnium oxide. Besides favorable properties, the material of choice must offer the possibility of reproduceable homogenous deposition at acceptable rates. The material properties should be adjustable, for example by thermal annealing, but must not change afterwards on a long term basis. Ta2O5 and HfO2 have been deposited by r.f. sputtering of high purity targets in Ar/O-2 mixtures. Due to the sensor application planned, thicknesses of 150 nm were deposited. The total thickness variation (TTV) across the whole 150 mm wafer was below +/-6%. After deposition, the layers were annealed with different methods. The mechanical stress can be adjusted through the annealing regime. The chemical inertness increases with the annealing temperature. All layers are insulating and transparent. Especially HfO2 annealed at 950 degreesC revealed favorable results: The layers are crystalline with a fine grained structure, smooth, dense and withstand NaOH as well as HF very well. It was verified, that these materials will be suitable for the applications desired, especially in contact with harsh environments. (C) 2003 Elsevier B.V. All rights reserved.