Hafnium oxide: A thin film dielectric with controllable etch resistance for semiconductor device fabrication
Hafnium oxide: A thin film dielectric with controllable etch resistance for semiconductor device fabrication
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DOI：
10.1063/5.0144639
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发表时间：
2023-06
期刊：
影响因子：
1.6
通讯作者：
A. Wratten;D. Walker;E. Khorani;B. F. M. Healy;N. Grant;J. Murphy
中科院分区：
文献类型：
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作者：
A. Wratten;D. Walker;E. Khorani;B. F. M. Healy;N. Grant;J. Murphy
薄膜介电材料在电子器件制造中普遍存在，在器件制造的各个阶段经常被沉积和刻蚀。我们证明了用原子层沉积方法在硅和预涂有氧化铝的硅上生长的HfO2薄膜具有耐腐蚀性能，这一特性可以通过改变沉积后的温度来调节。在氢氟酸(HF)溶液中，薄膜的刻蚀速率与退火温度有关，随着温度的升高，刻蚀速率降低。经X-射线衍射仪鉴定，蚀刻速率在300℃到350℃之间存在一个过渡区，对应于HfO2薄膜的结晶过程。直接沉积在350°C以上的硅上的HfO2薄膜在几个小时内耐受10%的HF溶液。在Si/Al_2O_3/HfO2堆栈的情况下，仔细检查发现存在沟道，这降低了HF酸的耐蚀蚀性能，这在硅衬底上的四甲基氢氧化铵刻蚀中得到了证明。晶化HfO2可以用来保护器件加工中的其他介质，我们展示了它在单面制造Al_2O_3图案化结构中的应用，这种结构可以控制硅片中用于调制太赫兹和毫米波辐射的有效电荷载流子寿命。
Thin film dielectrics are ubiquitous in the manufacture of electronic devices and are frequently deposited and etched away at various stages of device fabrication. We demonstrate that hafnium oxide (HfO2) thin films grown via atomic layer deposition on silicon and silicon pre-coated with aluminum oxide (Al2O3) have etch resistance properties, which can be tuned simply by changing the post-deposition annealing temperature. The etching rates of films in hydrofluoric acid (HF) solutions were found to be dependent on annealing temperature, with the etch rate decreasing with increasing temperature. A transition region in the etch rate was identified between 300 and 350 °C, corresponding to the crystallization of the HfO2 films, as identified via x-ray diffraction. HfO2 films deposited directly onto silicon annealed above 350 °C were resistant to 10% HF solutions over the course of several hours. In the case of Si/Al2O3/HfO2 stacks, closer inspection reveals the existence of channels, which reduces the etch resistance of HF acid, as evidenced by tetramethylammonium hydroxide etching of the silicon substrate. Crystallized HfO2 can be used to protect other dielectrics in device processing, and we demonstrate its use in single-sided fabrication of patterned structures of Al2O3, which can control the effective charge-carrier lifetime in silicon wafers for use in modulating THz and mm-wave radiation.