Vemuri Vamseedhara, King Sean W, Thorpe Ryan, Jones Andrew H, Gaskins John T, Hopkins Patrick E, Strandwitz Nicholas C
Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States.
Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124, United States.
ACS Appl Electron Mater. 2024 Jun 28;6(7):5173-5182. doi: 10.1021/acsaelm.4c00683. eCollection 2024 Jul 23.
Post deposition annealing of molecular layer-deposited (MLD) hafnicone films was examined and compared to that of hafnium oxide atomic layer-deposited (ALD) films. Hafnicone films were deposited using tetrakis(dimethylamido)hafnium (TDMAH), and ethylene glycol and hafnia films were deposited using TDMAH and water at 120 °C. The changes in the properties of the as-deposited hafnicone films with annealing were probed by various techniques and then compared to the as-deposited and annealed ALD hafnia films. In situ X-ray reflectivity indicated a 70% decrease in thickness and ∼100% increase in density upon heating to 400 °C yet the density remained lower than that of hafnia control samples. The largest decreases in thickness of the hafnicone films were observed from 150 to 350 °C. In situ X-ray diffraction indicated an increase in the temperature required for crystallization in the hafnicone films (600 °C) relative to the hafnia films (350 °C). The changes in chemistry of the hafnicone films annealed with and without UV exposure were probed using Fourier transformed infrared spectroscopy and X-ray photoelectron spectroscopy with no significant differences attributed to the UV exposure. The hafnicone films exhibited lower dielectric constants than hafnia control samples over the entire temperature range examined. The CF/O etch rate of the hafnicone films was comparable to the etch rate of hafnia films after annealing at 350 °C. The thermal conductivity of the hafnicone films initially decreased with thermal processing (up to 250 °C) and then increased (350 °C), likely due to porosity generation and subsequent densification, respectively. This work demonstrates that annealing MLD films is a promising strategy for generating thin films with a low density and relative permittivity.
对分子层沉积（MLD）铪酮薄膜的沉积后退火进行了研究，并与氧化铪原子层沉积（ALD）薄膜进行了比较。使用四（二甲基氨基）铪（TDMAH）沉积铪酮薄膜，在120°C下使用TDMAH和水沉积乙二醇和氧化铪薄膜。通过各种技术探测沉积态铪酮薄膜退火后的性能变化，然后与沉积态和退火后的ALD氧化铪薄膜进行比较。原位X射线反射率表明，加热到400°C时，薄膜厚度降低70%，密度增加约100%，但密度仍低于氧化铪对照样品。铪酮薄膜在150至350°C之间观察到最大的厚度减小。原位X射线衍射表明，铪酮薄膜结晶所需的温度（600°C）相对于氧化铪薄膜（350°C）有所升高。使用傅里叶变换红外光谱和X射线光电子能谱探测了有无紫外线照射下退火的铪酮薄膜的化学变化，未发现紫外线照射导致的显著差异。在所研究的整个温度范围内，铪酮薄膜的介电常数低于氧化铪对照样品。铪酮薄膜的CF/O蚀刻速率与350°C退火后的氧化铪薄膜的蚀刻速率相当。铪酮薄膜的热导率最初随热处理（高达250°C）而降低，然后升高（350°C），这可能分别是由于孔隙率的产生和随后的致密化。这项工作表明，对MLD薄膜进行退火是制备低密度和相对介电常数薄膜的一种有前景的策略。
