Metal vs. Metal Oxide Sputtering Targets for Reactive Sputtering

Thin film deposition is a critical process in industries such as electronics and optics. In sputtering applications, oxide coatings and other compound thin films are essential for tuning material properties and functional performance.

Understanding the process of depositing thin film oxides using reactive sputtering and metal oxide targets is necessary to optimize these processes and maintain consistent film characteristics.

1. Compound Materials For Thin Films

1.1. Description

Physical vapor deposition processes enable the deposition of a wide range of compound coatings, including nitrides, carbides, and fluorides. Achieving stoichiometric precision in these thin films is essential to ensure accurate elemental ratios and to produce coatings with specific material properties.

1.2. Examples

Oxide coatings are widely employed, including materials such as zinc oxide, aluminum oxide, and titanium oxide. Sputtering processes for these material span across applications such as OLED manufacturing or photovoltaics, where specific refractive indices, transparency, or other properties are required.

2. Metal Sputtering Targets

2.1. Introduction

Metal sputtering targets are often used in reactive sputtering, where reactive gases are introduced into the chamber to deposit oxides or other compounds. The metal atoms react with the oxygen to form films with specific stoichiometric ratios.

2.2. Characteristics

Metal sputtering targets are available and often offered in high purity grades (i.e. 99.999% purity), ensuring minimal contamination in the deposition process. By adjusting the rate of reactive gas into the chamber, this method offers flexible film stoichiometry. Characteristics to keep note of include:

• Target Lifetime: Pure metal targets will last longer than compound targets.
• Process: Reactive sputtering needs precise control to maintain stoichiometry is correct, requiring monitoring and care of the oxygen flow in the vacuum chamber.
• Poisoning: If the target surface reacts with the reactive gas, this can reduce deposition rates and interfere with the process.

3. Metal Oxide Sputtering Targets

3.1. Introduction

Another way of depositing metal oxide coatings is by using a metal oxide target with the required composition for film properties. These are designed to deposit stoichiometric films without requiring reactive gas.

3.2. Characteristics

Oxide targets, with their oxygen content already defined, serve in numerous sputtering applications. Depending on the material, metal oxide targets can be found in high purities. However, keep in mind the following:

• Availability: Some oxides may have less availability, making it difficult to readily source specific compounds needed by a process.
• Process: Metal oxides have lower deposition rates than elemental targets.
• Stoichiometry: Oxide targets may not yield fully stochiometric films in cases where sputter plasma can disassociate oxide molecules into metal and oxygen atoms.

Sourcing Sputtering Targets

For evaluating sputtering processes, the decision between reactive sputtering or metal oxide sputtering targets should be kept in mind. Depending on the use case in fields such as electronics, optics, or other applications, the streamlined used or level of control needed may be desired.

For applications requiring reliable, high-quality sputtering targets, R.D. Mathis Company supplies materials manufactured with controlled compositions and precise dimensional tolerances. Our experience in precision manufacturing supports the production of sputtering targets that meet stringent quality and performance requirements.

View standard available sizes and materials for elemental targets here.