Deposition of titanium nitride thin films by plasma enhanced atomic layer deposition has been realized on thermal silicon oxide substrates in an inductively coupled plasma reactor. The plasma step involves a H₂ (40 sccm)/N₂ (5 sccm)/Ar (10 sccm) gas mixture, and growth has been followed by in situ ellipsometric measurements. A tunable substrate bias voltage has been applied in the vicinity of the substrate to modulate plasma-ion energy and investigate its impact on the growth mechanism. We have observed that an increase in the applied bias power leads to a gradual TiN nucleation delay of up to 30 cycles at 80 W radio frequency bias power. An increase in the H₂ content of the plasma gas mixture shows that hydrogen species from the plasma can significantly deactivate the SiO₂ substrate, thanks to reduction reactions induced by H₃⁺, Ar⁺, and ArH⁺ ions leading to the formation of Si–H surface bonds. A nitrogen-rich plasma gas mixture results in N atom incorporation on the substrate surface, which in turn favors subsequent TiN growth. The combination of hydrogen-rich plasma chemistry with a high applied substrate bias power leads to a TiN growth delay larger than 50 cycles. These results provide a valuable implementation for the development of area-selective deposition processes.

中文翻译：

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等离子体增强原子层沉积过程中离子能量的控制：调节SiO2上TiN生长延迟的新策略

通过等离子体增强的原子层沉积来沉积氮化钛薄膜已经在感应耦合等离子体反应器中的热氧化硅衬底上实现。等离子步骤涉及H ₂（40 sccm）/ N ₂（5 sccm）/ Ar（10 sccm）气体混合物，生长之后进行原位椭偏测量。已经在基板附近施加了可调基板偏置电压，以调制等离子体离子能量并研究其对生长机理的影响。我们已经观察到，在80 W射频偏置功率下，施加偏置功率的增加会导致TiN逐渐成核延迟，最多可达30个周期。H ₂增加等离子体气体混合物的含量表明，由于H ₃ ⁺，Ar ⁺和ArH ⁺离子引起的还原反应导致Si-H表面键的形成，等离子体中的氢物种可以使SiO ₂基材显着失活。富含氮的等离子气体混合物会导致N原子掺入基材表面，从而有利于随后的TiN生长。富氢等离子体化学与高施加的衬底偏置功率的结合导致TiN的生长延迟大于50个循环。这些结果为开发区域选择性沉积工艺提供了有价值的实现。