Copper interconnects in modern integrated circuits require a barrier layer to prevent Cu diffusion into surrounding dielectrics. However, conventional barrier materials like TaN are highly resistive compared to Cu and will occupy a large fraction of the cross-section of ultra-scaled Cu interconnects due to their thickness scaling limits at 2–3 nm, which will significantly increase the Cu line resistance. It is well understood that ultrathin, effective diffusion barriers are required to continue the interconnect scaling. In this study, a new class of two-dimensional (2D) materials, hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS₂), is explored as alternative Cu diffusion barriers. Based on time-dependent dielectric breakdown measurements and scanning transmission electron microscopy imaging coupled with energy dispersive X-ray spectroscopy and electron energy loss spectroscopy characterizations, these 2D materials are shown to be promising barrier solutions for Cu interconnect technology. The predicted lifetime of devices with directly deposited 2D barriers can achieve three orders of magnitude improvement compared to control devices without barriers.

现代集成电路中的铜互连需要阻挡层，以防止Cu扩散到周围的电介质中。但是，常规阻挡层材料（如TaN）与Cu相比具有高电阻性，并且由于其在2–3 nm处的厚度缩放限制而将占据超尺度Cu互连的横截面的很大一部分，这将显着增加Cu线的电阻。众所周知，需要超薄，有效的扩散势垒来继续进行互连缩放。在这项研究中，一种新型的二维（2D）材料，即六方氮化硼（h-BN）和二硫化钼（MoS ₂），作为替代性的Cu扩散势垒而被探索。基于随时间变化的介电击穿测量，扫描透射电子显微镜成像，能量色散X射线光谱学和电子能量损失光谱学表征，这些2D材料被证明是铜互连技术的有希望的阻挡层解决方案。与没有障碍物的控制设备相比，具有直接沉积的2D障碍物的设备的预计寿命可以提高三个数量级。