On the same wavelength

Plansee helps operators of MOCVD reactors to increase the service life and the productivity of the systems with an optimized design and a patented coating for the heating elements.

A porous tungsten coating increases the surface area of the heating elements, with the result that they radiate more heat.

MOCVD is the most important process used in manufacturing LEDs. The process creates the active semiconductor layers that emit the light. White LEDs require a gallium nitride layer, and this is deposited using MOCVD. The abbreviation stands for metal organic chemical vapor phase deposition. It is an epitaxial process for creating crystalline semiconductor layers such as those used in LEDs, solar cells and other opto-electronic components. Temperatures in excess of 1000 °C are needed to create gallium nitride (GaN) in MOCVD reactors.
To achieve such temperatures, it is necessary to bring the heating elements in the furnace to a temperature of up to 2000 °C. And these high temperatures mean that it is necessary to use the high-performance materials molybdenum and tungsten, along with their alloys. A range of different shield packs, gas manifolds and heating elements are used, and Plansee supplies more than 50 different components for some reactor types. Plansee is not only an original equipment manufacturer for reactors. They are also active in the spare parts market. Plansee also helps operators of MOCVD reactors to increase the service life and the productivity of the systems with an optimized heating element design and a patented coating for these heating elements.

Light of the same wavelength
The aim of the manufacturers is to ensure that the semiconductor layers emit light of the same wavelength. In the MOCVD process, this goal is best achieved if the temperature distribution at the wafer is as homogeneous as possible. The wafer is the carrier for the semiconductor layer and is made of sapphire, for instance. Any discrepancy in the temperature profile leads to a change in the color of the LED. Therefore, Plansee optimizes the design of the heating elements to meet the customer’s requirements. Plansee’s engineers carry out complex finite element calculations to simulate the conditions in the reactor and optimize the design of the different heating components. The aim is to achieve greater homogeneity of the temperature throughout the reactor and match the temperature profile to the process used by the customer. The customer benefits from a greater yield from each coating cycle and thus from increased productivity.

Heating elements that emit more heat
The more heat the heating elements can radiate in the reactor, the less they need to be heated up. Plansee has developed a patented coating process. The tungsten-based coating is very porous. This greatly increases the surface area of the heating elements, which results in more heat being radiated. The benefit for the customer: The lower working temperature reduces power consumption and extends the service life of the heating elements by several months. This in turn reduces the cost of manufacturing LEDs.