Specific Process Knowledge/Thin film deposition/ALD Picosun R200: Difference between revisions
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Each process is using two (or three for AZO) different precursors. The reaction takes place in cycles. During each cycle, a very short pulse of each precursor is introduced into the ALD reaction chamber in turns, and in-between each precursor pulse the chamber is purged with nitrogen. All reactions have to take place on the sample surface, thus it is very important that each precursor is removed from the chamber before the next one is introduced. In that way, materials can be deposited atomic layer by atomic layer by ALD. | Each process is using two (or three for AZO) different precursors. The reaction takes place in cycles. During each cycle, a very short pulse of each precursor is introduced into the ALD reaction chamber in turns, and in-between each precursor pulse the chamber is purged with nitrogen. All reactions have to take place on the sample surface, thus it is very important that each precursor is removed from the chamber before the next one is introduced. In that way, materials can be deposited atomic layer by atomic layer by ALD. | ||
In order to ensure that the ALD reactor has the same temperature everywhere, it has a dual chamber structure. The inner chamber is the ALD reactor | In order to ensure that the ALD reactor has the same temperature everywhere, it has a dual chamber structure. The inner chamber is the ALD reactor, and the outer chamber is a vacuum chamber that is isolating the reactor from room air. The space between the two chambers is called an intermediate space (IMS), and this is constantly purged with nitrogen. One or more wafers or samples are placed in a sample holder in the inner chamber. | ||
When the reactor chamber is heated up or cooled down, it will take some time before the sample holder and the sample reaches the desired temperature. Thus, it is important to include a temperature stabilization time in the process recipes. | When the reactor chamber is heated up or cooled down, it will take some time before the sample holder and the sample reaches the desired temperature. Thus, it is important to include a temperature stabilization time in the process recipes. | ||