Conventional chemical deposition techniques trigger film growth through nucleation and grain growth, which may exhibit properties of non-uniform thickness and presence of pin-holes. The heat-intensive processes may also render mechanical instabilities on the materials, and give rise to higher capital costs. Furthermore, such techniques may not allow full coverage of complex geometries. To overcome these challenges, an improved technique has been introduced.
This technology is known as atomic layer deposition (ALD) and is considered a derivative of the chemical vapour deposition (CVD) technique. It breaks the continuous CVD method into 2 (or more) sequential, self-limiting steps that are highly insensitive to excess amount of precursors and process duration. As opposed to CVD where the deposition of films is achieved through thermal decomposition of molecules, the build-up of film in ALD is achieved through chemical reactions on the substrate surface, between two highly reactive precursors that are introduced into the process chamber in an alternating fashion. This crucial difference allows very precise control of thickness and high uniformity over large areas of high aspect ratios. Due to the digital nature of the process, growth of single, multi and mixed layers are possible.
With the application of this technology:
This technology has the following features:
This technology is commonly used to deposit conducting oxides (AZO, ATO), semiconductors (TiO2, ZnO, TiN, AlN, ZnS, Sb2S3), insulators (Al2O3, SiO2, HfO2, In2O3, TiO2, ZrO2, Ta2O5, ZnO, SnO2 NiOx, Fe3O4), and metals (Pt, Ru, Pd).
The potential applications include (but are not limited to) the following:
The global atomic layer deposition equipment market was valued at USD 875.0 million in 2015 and is estimated to grow at a CAGR of 29.4% and reach USD 8.6 billion by 2024. In 2015, Asia Pacific held the largest market share for atomic layer deposition equipment, accounting more than 52% of total market size. China is leading the atomic layer deposition equipment market in Asia Pacific. Increasing growth of semiconductor industry across Asia Pacific due to the presence of cheap skilled labour, land and government subsidies are simultaneously boosting the usage of ALD in this region. Growing application of ALD equipment in the field of electronic industry in the emerging markets of China, Japan, Taiwan and South Korea is fueling the demand for ALD equipment across Asia Pacific. [Source: EuroPlat.org, 27 Jul 2016]