Flow Control in MOCVD Applications

• Metalorganic Chemical Vapor Deposition (MOCVD) requires stable and accurate gas flow to create uniform, high quality products such as LED lights.
• Additionally, fast control and optimized flow controller settings are crucial for quality MOCVD processes.
• The EL-FLOW from Bronkhorst, combined with the right engineering support, can offer a high performing MOCVD process.

Bronkhorst mass flow controllers play an indispensable role in the manufacturing of LEDs by metalorganic chemical vapor deposition (MOCVD). A stable and accurate flow control of hydrogen gas results in improved MOCVD process conditions. Thereby, product quality of the LED also improves.

Metalorganic chemical vapor deposition is a critical manufacturing step in LED light production. And in metalorganic CVD processes, a carrier gas guides one or more vaporous organometallic compounds to a wafer. There, these compounds decompose and deposit very thin crystalline layers on the wafer. This process makes red, green, or blue emitting LEDs. Generally, some kind of nitride is used, which determines the light color to be emitted.

A large manufacturer of mini-LEDs for TV screens uses MOCVD with hydrogen as carrier gas. They requested the help of Bronkhorst for a reliable and stable solution to supply this carrier gas.

Importance of Flow Control in MOCVD Applications

This customer requires more accurate flow control of hydrogen gas supply to improve their MOCVD process. Thus, the improved process will increase the quality of their LEDs. The implementation of stable flow conditions, a fast response, and changes in the settings from the flow controller improve the overall process.

• stable mass flow control for hydrogen gas
• fast control
• optimized instrumentation settings

Improving LED Manufacturing with Optimized Flow Control in MOCVD Processes

To improve the quality of the MOCVD process and therefore the LED quality, Bronkhorst recommends multiple EL-FLOW Metal Sealed mass flow controllers as standard devices inside the AIXTRON generation G3/G4 MOCVD equipment. And the aim of these flow controllers is to control the hydrogen carrier gas flow. A stable carrier gas flow is key to the quality of the entire process, as its flow rate determines the deposition rate of LED components.

These Bronkhorst mass flow controllers supply a lot of gas to fill the chambers of the MOCVD reactor equipment. So several different types are used: small EL-FLOW mass flow controllers with typical gas flow rates of 20 ml/min ranging to large ones with flow rates of 20 l/min. The metal-to-metal seal construction with excellent resealing capability are unique features of the EL-FLOW Metal Sealed mass flow controllers. Moreover, they have a high-quality surface that makes them highly suitable for the stringent requirements in semiconductor and solar industries.

Using these devices results in a highly stable hydrogen gas flow rate with a fast response time to changes in process conditions. This improvement will lead to cost reductions as well as to reduction of stock items. 

Engineering Support for Flow Instrumentation

In addition to engineering support, Bronkhorst performs calibrations and repairs to flow devices, even if they are 10 years old. Besides that, our team will support customers on-site for advice on how to use the flow devices and give tips on how to improve their process. For this project, the service team helps the customer fine-tune the process by adjusting the PID settings of the mass flow devices to get a better control performance in the MOCVD system.