HfxZr1 − xO2 thin films for semiconductor applications: An Hf- and Zr-ALD precursor comparison

In the last few years, hafnium oxide (HfO2), zirconium oxide (ZrO2), and their intermixed system (HfxZr1 − xO2) have aroused more and more interest due to their outstanding properties in the frame of semiconductor applications. Different mixtures of these two sister materials, i.e., different Hf:Zr ratios in HfxZr1 − xO2 layers, as well as different crystal arrangements come with a wide set of structural and electrical properties, making this system extremely versatile. Starting from an amorphous layer, the different crystalline phases are easier to be targeted through subsequent thermal treatment. A correct understanding of the deposition process could help in obtaining films showing the addressed material properties for the selected application. In this paper, a comparison of Hf- and Zr-atomic layer deposition precursors is conducted, with the goal of depositing an almost amorphous HfxZr1 − xO2 layer. Material composition is tuned experimentally in order to address the properties that are relevant for the semiconductor industry. The observed trends are examined, and guidelines for applications are suggested.