PICVD is based on a new principle of the formation of organometallic vapour phase. A simple idea became a basis of this principle - the whole amount of precursors mixture must be stored cool, only their microdoses can be introduced into evaporator. This idea allowed to elaborate a simple and precise liquid delivery system for CVD sources based on the principle used for the control of fuel injection in the latest thermal motors.The injected microdose is evaporated instantaneously (flash evaporation), thus there is no time for chemical changes of precursors.
Volatile organometallic precursors or their mixture (e.g., Y, Ba, Cu b-diketonates for YBCO deposition) are dissolved in appropriate organic solvent. The precise microdoses of solution are injected into evaporation zone by means of computer-driven injector, where they instantly evaporate. The resulting mixture of solvent and precursor vapour is transported by carrier gas (Ar, O2) into high temperature zone where the decomposition reaction and film growth on a substrate occurs. Injector is a high speed micro electro-valve
The advantageous features of PICVD:
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