Bubbler cylinder

A bubbler or bubbler system, sometimes referred to as Dampfdrucksättiger is a part of a plant for the metal organic chemical vapor deposition ( MOCVD). Its purpose is to give the initial substances ( precursors ) to convert used organometallic compounds in a saturated vapor and these using initi ended gas bubbles of an inert carrier gas (argon, nitrogen or hydrogen) by entrainment controls to lead into the reaction chamber.

Construction

The container of the corresponding Bubblers after his construction of a gas washing bottle and used the protected storage Metallorganikum under the absence of air (oxygen, moisture). The Bubbler usually equipped with an inlet pipe and an extraction tube. The inlet tube ends down just before the ground. In this pipe, an inert gas is introduced, and bubbling through the liquid chemical. For a fixed chemical sublimates. Through the draw tube exits the bubbler, the mixture of controlled inert gas introduced and evaporated in a downstream chemical reactor. The temperature is controlled by a thermostat, so that a defined, constant vapor pressure can be achieved. The supply of the most expensive and sensitive chemical is controlled by the controlled flow of the inert gas and the temperature of the bubbler, which results from the vapor pressure of the chemical.

The piping between the bubbler and the reaction vessel has a higher temperature than the bubbler, otherwise the precursor condenses in the pipe and is thus introduced uncontrolled as drops to the reaction vessel. Does this happen with a solid precursor, the line may become clogged. A disadvantage of these methods of Prekursorzuführung is that the precursor can be degraded by the heating.