From LEDs to microprocessors
By means of our leading material-coating technologies, we are an influential, key-enabling technology provider to many emerging markets in the fields of compound, silicon, and organic semiconductors, as well as nanomaterials. For our customers, this means they have access to a wide selection of technologies for manufacturing a diverse range of devices.
The MOCVD volume production systems are based on the planetary concept (Planetary Reactor) designed by Philips and continuously enhanced by AIXTRON. The reactors can accommodate substrates from 2 to 8 inches (200 mm).
The Planetary Reactor is based on the principle of a horizontal laminar flow reactor. It ensures extremely precise transitions among various materials and unrivaled control of the deposition rates in a thickness range of several atoms. Combining this principle with the multiple rotation of substrate carriers, ensures that deposition occurs with excellent homogeneity with regard to film thickness, composition, and doping. In addition, the special reactor inlet, which permits the separation of several gases, ensures an externally even radial flow with optimally adjustable distribution.
The reactors are inductively heated and can be equipped with a wide range of in situ sensors.
The Close Coupled Showerhead (CCS) design permits a number of susceptor substrate configurations up to a maximum capacity of 69x2 or 19x4-inch wafers, that are used for the volume production of GaN-based components.
In Close Coupled Showerhead technology, the process gases are introduced into the reactor over the entire coating surface via the water-cooled showerhead surface. Accordingly, the distance between the showerhead and the substrates is very small. The gas inlet is designed in such a manner that the Group III and Group V gases are separated by means of many small tubes until entering the reactor. The gases are introduced into the reactor through separate openings in the showerhead to achieve a even distribution of process gases.
The substrates lie on a rotating susceptor heated by a resistance heater. Separate heating zones enable the temperature profile to be adjusted in such a manner that the susceptor always has the same temperature over its entire surface.
AIXTRON offers a revolutionary technology for the deposition of organic semiconductor materials to produce organic light-emitting diodes (OLEDs) and flexible electronics for use in flat-screen monitors and lighting, as well as other semiconductor applications. OVPD is an innovative technology for thin-film deposition of organic small molecules based on the gas phase transport principle.
Maximum productivity at low operating costs
In a process developed and patented by Prof. Stephen R. Forrest from Princeton University, USA, the organic materials vaporize in a fine vacuum and are transported by means of an inert carrier gas to the substrate where deposition takes place. Compared to conventional methods (Vacuum Thermal Evaporation - VTE), this technology presents major advantages relating to process control, reproducibility, and operating costs.
US-based Universal Display Corp. (UDC) holds the usage rights for the OVPD patents, and licensed them exclusively to AIXTRON in 1999 for the development, production, and marketing of OVPD systems.
With UDC’s support, AIXTRON has developed OVPD production systems that focus on OLED technology requirements. To this end, AIXTRON combined OVPD with the patented Close Coupled Showerhead (CCS) technology, which is already being successfully used in other AIXTRON deposition systems (MOCVD) for the volume production of semiconductor devices.
PECVD to deposit flexible barrier films for thin-film encapsulation
PECVD systems are widely used for the deposition of dense inorganic thin-films acting as water and oxygen permeation barriers. Conventional parallel plate PECVD technologies, however, involve inherent challenges and shortcomings when applied in volume manufacturing display operations.
These challenges and shortcomings include:
- High process temperatures of typically more than 250˚C are required to deposit high-quality films at the film growth rates necessary to ensure high productivity for mass production. In OLED manufacturing, such temperatures would immediately destroy sensitive organic layers.
- The resultant limitation in deposition rates can be addressed by adding numerous parallel plate chambers for mass production. This, of course, will reduce capital efficiency and add costs for the encapsulation process.
- Display production is moving towards larger substrate sizes to realizes economy of scale effects. The scale-up then requires a high degree of uniformity to ensure consistent optical performance. The required uniformity levels then are increasingly difficult to achieve on parallel plate PECVD systems.
The linear source design of AIXTRON’s proprietary OPTACAP™ technology combines easy scaling to any substrate size with high deposition rates at low substrate temperatures. It yields barrier films offering unprecedented flexibility and ensuring low surface stress to the underlying substrate.
With its PVPD technology, AIXTRON offers an innovative approach for the controlled gas-phase deposition of polymer-based thin films. The technology is geared toward the deposition of functional thin-film structures and is able to convert various polymerization processes into this scalable procedure. While conventional polymerization procedures involve solvent-based technologies, PVPD technology is based on the principle of carrier gas-supported gas phase deposition.
The precursor materials, generally consisting of monomers, are vaporized in specially optimized source systems and supplied to the deposition process via an inert carrier gas. By using AIXTRON’s patented Close Coupled Showerhead (CCS) technology, the process is scalable to any substrate size and can also be used in batch-based procedures, as well as continuous inline or roll-to-roll processes. The ability to precisely control the supplied material quantities enables the deposition of complex compounds, e.g., by means of controlled copolymerization.
Thanks to the flexible, modular setup, systems can be optimized for various polymerization processes and thus serve a broad scope of applications. The process enables one to precisely control the film thickness and obtain excellent homogeneity of the deposited films.
Thanks to the solvent-free procedure, drying steps are no longer necessary and the films can be deposited in a contour-conforming manner. The moderate process temperatures permit deposition of almost any substrate material, including organic ones.
Typical applications include functional polymer films for surface functionalization (e.g., hydrophobic or oleophobic layers) and the deposition of functional films as used in organic electronics, barrier layers, and many others.
The warm-wall CVD systems are used for manufacturing semiconductors with a large electronic band gap, such as silicon carbide (SiC) for example. In these systems, the concept of the planet reactor is combined with the high-temperature process. Able to accommodate up to 5x200mm wafers, these systems are among the world’s largest commercial CVD production facilities for SiC. The key advantages of this method include an unmatched production capacity and the effective use of precursor materials.
Silicon carbide for the future
Silicon carbide (SiC) is a semiconductor material that is exceptionally well-suited for high-power and high-frequency electrical applications. Fast, low- loss SiC Schottky diodes provide efficient and compact solutions for circuit network components that are currently being used in computer servers. Power rectifier modules, which can be designed to be more compact and lightweight thanks to SiC rectifiers and transistors, show considerable promise for future use in hybrid or electric vehicles.
In this system, the horizontal warm-wall reactor is combined with Gas Foil Rotation (GFR). During the coating process, the rotation of the substrate produces very homogeneous films that are required for modern high-performance devices. The patented transfer system enables the reactor to be manually loaded with the substrate carriers and unloaded. Upon request, a second deposition chamber can be provided that gives the system greater flexibility and higher throughput.
AIXTRON’s unique plasma-based deposition technology makes the growth process very flexible and allows different nanomaterials to be produced. The plasma complements the chemical vapor deposition process and enables almost all variants and shapes of graphene, carbon nanotubes and nanowires to be synthesized, as well as lowering process temperatures and making possible different surface preparations.
AIXACT®, AIXTRON®, APEVA®, Atomic Level SolutionS®, Close Coupled Showerhead®, CRIUS®, EXP®, EPISON®, Gas Foil Rotation®, Optacap™, OVPD®, Planetary Reactor®, PVPD®, STExS®, TriJet®