Improving Atomic Layer Deposition Process of Silicon Oxide (SiO²)

Due to film uniformity issues and material wastage caused by changes in the hardware setup of the atomic layer deposition (ALD) equipment, the bis(diethylamino)silane (SiBDEA))ozone oxygen mixture ($\mathrm{O}_{3} / \mathrm{O}_{2}$) silicon oxide (SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>) process of this equipment needs to be re-optimized urgently. After the experiment with method design of experiments (DoE), a new recipe for the SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> process was discovered. On the one hand the film properties were comparable to the old process, and with the new recipe the material consumption could be reduced to $50 \%$. On the other hand, the temperature range of $150^{\circ} \mathrm{C}-300^{\circ} \mathrm{C}$ showed no ALD window, in contrast to the literature [1]. The purpose of this SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ALD film is an application as protective films in some microelectromechanical systems (MEMS) devices, such as protecting structures from etching with Xenon difluoride (XeF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>). [2] It was proved that the minimum cycle number for an effective protective film deposited with the new recipe is at least 50, this means thickness of about 4.5 nm.