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。这使得能够定制材料，包括它们的光学、电学和磁性。在各种方法中，溅射是一种物理气相沉积技术，其基于离子与靶碰撞，材料从靶分离并沉积在基板上。在磁控溅射（MS）中，限制在靶表面附近的电磁场用于使惰性气体扩散并产生等离子体，由此产生离子并加速以轰击靶材料，从而获得高质量均匀的薄膜。虽然沉积速率与离子的数量成比例，但使用高压惰性气体是诱人的，但这是以在结构和密度方面低质量的膜为代价的。因此，MS的限制因素是沉积速率低，从而限制了该技术的工业应用。与INRS-EMT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MS与20 Hz纳秒UV激光器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，以实现高质量的薄膜。由于达到烧蚀阈值所需的通量在较低的脉冲持续时间下降低，脉冲持续时间的平方根为倒数（低至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。利用超快激光系统，我们将研究从0.04到10 ps的超短脉冲的MS/PLD。此外，超短脉冲激光以高得多的重复率操作，从而提供了研究MS/PLD缩放到更高的激光重复率以增加沉积速率的可能性（例如，5 kHz对20 Hz表示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).