Laser assisted magnetron sputter deposition with ultrashort pulses

薄膜和纳米结构的制造可以通过各种技术来实现。这使得材料的剪裁，包括其光学，电学和磁性。在各种方法中，溅射是一种物理气相沉积技术，它是基于离子与靶体碰撞，从中分离出材料并沉积在基板上。在磁控溅射（MS）技术中，利用靠近靶材表面的电磁场使惰性气体电离并产生等离子体，等离子体产生离子并加速轰击靶材，从而获得高质量的均匀薄膜。虽然沉积速率随离子数量的增加而增加，但使用高压惰性气体是诱人的，但这是以低质量薄膜的结构和密度为代价的。因此，质谱的限制因素是沉积速率低，从而限制了该技术的工业应用。近年来，我们的工业合作伙伴Plasmionique Inc.与INRS-EMT的研究人员合作，开发了一种称为MS/PLD（脉冲激光沉积）的混合技术。他们已经证明，将质谱与20赫兹纳秒紫外激光与目标相互作用相结合，可以保持高沉积速率，同时保持足够低的压力，从而实现高质量的薄膜。由于在较低的脉冲持续时间下，达到烧烧阈值所需的能量减少，脉冲持续时间的平方根的倒数（降至1皮秒- ps -脉冲持续时间），我们假设MS/PLD将受益于使用超短脉冲来触发和维持磁控管放电。使用超快激光系统，我们将以0.04至10 ps的超短脉冲研究MS/PLD。此外，超短脉冲激光以非常高的重复率工作，从而为研究MS/PLD的比例提供了可能性，以提高激光重复率以增加沉积速率（例如5 kHz vs 20 Hz代表125倍）。

The fabrication of thin films and nanostructures can be realized through various techniques. This enables the tailoring of materials including their optical, electrical, and magnetic properties. Among the various approaches, sputtering is a physical vapour deposition technique which is based on ions colliding with a target from which material is detached and deposited on a substrate. In magnetron sputtering (MS), an electromagnetic field confined near the surface of the target is used to ionize the inert gas and to create aplasma, from which ions are produced and accelerated to bombard the target materials from which high quality uniform thin films are obtained. While the rate of deposition scales with the number of ions, it is tempting of using a high pressure of inert gas, but this comes at the costs of low quality films in terms of structure and density. Therefore, the limiting factor for MS is a low rate of deposition thus limiting the industrial applications of this technique.Over the recent years, our industrial partner Plasmionique Inc. has developed, in collaboration with INRS-EMT researchers, a hybrid technique called MS/PLD (Pulsed Laser Deposition). They have demonstrated that combining MS with a 20 Hz nanosecond UV laser interacting with the target allows the retention of a high rate of deposition while keeping the pressure sufficiently low enough to enable high quality films. As the fluence needed to reach the ablation threshold is reduced at lower pulse duration, with the inverse of the square root of the pulse duration (down to 1 picosecond - ps - pulse duration), we hypothesize that MS/PLD will benefit fromthe use of ultrashort pulses for triggering and maintaining the magnetron discharge. Using ultrafast laser systems, we will study MS/PLD with ultrashort pulses from 0.04 to 10 ps. Furthermore, ultrashort pulsed laser are operated at much high repetition rate, thus offering the possibility of studying the scaling of MS/PLD to higher laser repetition rate for increasing the rate of deposition (e.g. 5 kHz vs 20 Hz represents a factor of 125).