Phase and structural evolution of sol–gel synthesized ZrO2/Si thin films under heat treatment

Abstract

ZrO 2 /Si thin films were fabricated using a solgel technique, and the chemical state change and structural evolution from sol to gel to Zr oxide by heat treatment were investigated. The precursor sol was synthesized using a Zr-acetylacetonate (Zr-acac) precursor, spin-coated, dried on Si(100) substrates, and then annealed at 300-700°C in air. With increased annealing temperature of the sol-gelderived layer, Zr-acac decomposed into Zr-acetate, an amorphous ZrO 2 phase formed, and crystallization into a tetragonal phase occurred. In addition, the ZrO 2 layer became denser and the interfacial layer between ZrO 2 and Si thickened, whereas the surface morphology was nearly unaffected and remained smooth with root-mean-square values \ 4.5 Å .

Spray‐Pyrolyzed High‐k Zirconium‐Aluminum‐Oxide Dielectric for High Performance Metal‐Oxide Thin‐Film Transistors for Low Power Displays

“…The weight loss in the first stage is ascribed to the evaporation of organic solvent. [ 36–39 ] A gentle weight loss is observed in the second stage between 117 and 186 °C. In this stage 4.91% weight is lost, which might be due to the desorption of physically adsorbed water, remaining organic solvent, and AcAc complexes.…”

“…[ 36,40 ] Note that an exothermic peak appears at 154 °C, indicating the decomposition of Zr‐AcAc and Al‐AcAc into Zr‐Acetate and Al‐Acetate, respectively. [ 38,41,42 ] In addition, more weight loss is observed in the third stage between 187 and 361 °C. Only 1.13% weight loss is found in this stage.…”

Growth and electrical properties of spin coated ultrathin ZrO2 films on silicon

“…The dielectric breakdown field of the film is found to be 6.29-8. 15 In the recent years, oxide thin films, like ZrO 2 , HfO 2 , Pb(Zr Ti)O 3 , BiFeO 3 , MgO, ZnO, etc., have received significant attention in numerous applications such as protective and thermal barriers, optical filters, thin film capacitor, metal-oxide-semiconductor (MOS) transistor, micro-electromechanical system (MEMS), biomaterials, superconductor, multiferroic, and other diverse areas. [1][2][3][4][5][6] Out of these application, present day MOS technology demands deposition of ultrathin metal oxide films, having thickness 50 nm or less, to replace SiO 2 as gate insulator.…”

“…[7][8][9][10][11][12][13][14] Although the integration of many of these oxide films on silicon remains a huge challenge mainly due to the stability and interfaces of these oxide with the Si substrate, ZrO 2 is one of the most promising material in the field of MOS technologies because of its excellent thermal, chemical, and mechanical stability with silicon, high dielectric constant, and large band gap. [7][8][9][10][11]15,16 Ultrathin ZrO 2 films, for MOS devices applications, are mainly deposited by vacuum-based methods like evaporation, 17,18 sputtering, 1,12,14,16,19 metal-organic chemical vapor deposition (MOCVD), 7,20 atomic layer deposition (ALD), 9,11,13,21,22 and pulsed laser-ablation deposition (PLD). 23 The use of liquid-based procedures, such as solgel, for exploration of MOS devices, has been published in literatures before, 5,6,24 but has been restricted to relatively thick films (>180 nm).…”