Direct Determination of Medium Range Ordering in Amorphous Hydrogenated Boron Carbide for Low-k Dielectric Applications
Direct Determination of Medium Range Ordering in Amorphous Hydrogenated Boron Carbide for Low-k Dielectric Applications
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直接测定低 k 电介质应用中非晶态氢化碳化硼的中程有序度
DOI：
10.1017/s143192762001394x
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发表时间：
2020
影响因子：
2.8
通讯作者：
Hwang, Jinwoo
中科院分区：
文献类型：
--
作者：
Gharacheh, Mehrdad Abbasi;Im, Soohyun;Johnson, Jared;Ortiz, Gabriel Calderon;Zhu, Menglin;Oyler, Nathan;Paquette, Michelle;Rulis, Paul;Sakidja, Ridwan;Hwang, Jinwoo
在过去的几十年里，微处理器的频率从66MHz增加到4ghz，而尺寸从1 μm减小到90nm。随着互连尺寸的减小（图1a），导体的电阻和绝缘体的电容增大，导致集成电路的电阻-电容（RC）延迟增大。减小导体的电阻或介质的电容对于提高晶体管的集成度和减小RC延迟是非常重要的。为了实现这一目标，人们一直在努力用新一代低介电常数(k)材料替代传统的SiO2。同时，具有稳定的机械和热性能以及低介电常数是至关重要的[2-3]。非晶氢化碳化硼（a- bc: H）是一种理想的选择，它既具有适当的机械性能，又具有低介电常数。采用等离子体增强化学气相沉积（PECVD）技术，以邻碳硼烷为前驱体[4]生长a- bc: H薄膜，其结构和组成变化很大。无定形氢化碳化硼的理论建模表明，a-BC: H的原子结构包含12顶点的二十面体簇，这归因于短程有序（SRO，图2b）[5]。这些SRO集群可以聚集并形成中程排序（MRO）。然而，目前尚不清楚这些模拟的MRO信息是否准确，因为一些模拟参数（如时间尺度）与实际生长条件有很大不同。如果对MRO参数进行了适当的表征，将为我们提供通过精确控制PECVD生长条件来控制非晶膜性能的机会。然而，MRO表征一直具有挑战性，因为传统的成像或衍射技术往往对MRO不敏感。
During past decades, the frequency of micro-processors has increased from 66MHz to 4 GHz while their sizes have decreased from 1 μm to 90 nm. As the size of interconnections (Fig. 1a) reduces, the conductors’ resistance and insulators’ capacitance increase, leading to increase in Resistance-Capacitance (RC) delay of ICs. It is important to decrease either conductors’ resistance or dielectrics’ capacitance to have more densely integrated transsitors and less RC delay [1]. To achieve this, there have been ongoing efforts to substitute traditional SiO2 with new generation of low dielectric constant (k) materials. Simultaneously, it is crucial to have stability in mechanical and thermal properties along with low dielectric constant [2-3].Amorphous hydrogenated boron carbide (a-BC: H) is a desired option containing both proper mechanical properties and low dielectric constant. The a-BC: H films can be grown using plasma enhanced chemical vapor deposition (PECVD) with ortho-carborane precursors [4], which results in a wide range of variation in the structure and composition. Theoretical modeling of amorphous hydrogenated boron carbide has suggested that atomic structure of a-BC: H contains 12-vertex icosahedral clusters which are attributed to short range ordering (SRO, Fig. 2b)[5]. These SRO clusters may gather and form the medium range ordering (MRO). However, it is currently not clear whether MRO information from these simulations is accurate since some simulation parameters (such as the time scale) are substantially different from the real growth conditions. The MRO parameters, if properly characterized, will provide us the opportunity to control the properties of the amorphous films by precisely controlling the PECVD growth conditions. However, MRO characterization has been challenging because conventional imaging or diffraction techniques tend to be insensitive to MRO.