Application areas of ALD technology
Since the process temperature of ALD deposition is low compared to conventional CVD processes, ALD films can be deposited especially on integrated circuit substrates, i.e., CMOS wafers. Thus, ALD technology can be used for various MEMS, NEMS or CMOS-related applications, such as:
- Cost-effective 3D NEMS technologies for the generation of free-standing nanostructures on CMOS surfaces with highest reproducibility have been developed and patented by Fraunhofer IMS
- Media-resistant coatings for sensor applications such as pressure sensors or for encapsulating medical implants. Aluminum oxide (Al2O3) and tantalum pentoxide (Ta2O5) are available as ALD passivation. Upon request, further ALD materials can be implemented at Fraunhofer IMS
- Electrical or optical shielding can be produced by metallic layers such as ruthenium (Ru). In addition, ALD layers can be used as transparent conductive electrode layers, e.g. for optical sensors or solar cell applications
- Due to the high conformality of the ALD process, dielectrics can be ideally used as insulation in trench capacitors. High- and medium-k dielectrics are available for trench capacitors. Fraunhofer IMS has experience in the development of trench capacitors for high temperature applications (more than 250 °C) based on ALD layers.
ALD technology offers the possibility to realize free-standing 3D MEMS or NEMS structures with wall thicknesses in the nanometer range on CMOS surfaces. The combination of different ALD materials enables the exact tuning of the physical and chemical parameters of the free-standing structure. Due to the nanoscale wall thickness and a low mechanical as well as thermal mass, the 3D structures are ideally suited for advanced sensor applications in gas or biosensing. Furthermore, nanowires, ultrathin membranes and cantilevers are fabricated at Fraunhofer IMS using ALD technology.
Special solutions for arbitrarily shaped components, such as packaged sensors or coatings with special materials, can be realized on request.