Injection Method

The following list covers the major steps involved in vaporizing a liquid source and supplying it to the process chamber.

  1. The liquid source's flow rate is measured, and the amount of liquid is feedback controlled by the valve.
  2. The liquid is instantaneously and completely vaporized.
  3. The gas is released without being allowed to condense back into its liquid form.

Vaporization systems that use the injection method sequentially carry out steps 1, 2, and 3 listed above. The VC series units measure the liquid flow of the liquid source using a mass flow meter, and do not use a carrier gas. The MI/MV series units use a mass flow meter for measurement, and feature a mass flow controller that introduces a carrier gas into the unit to vaporize the liquid source.

Triple Point

The graph above shows the different possible states of matter. There are two ways to get from a liquid to a gaseous state. The first method involves increasing the temperature while holding the pressure steady, as indicated by the arrow with the broken line broken line. This method is commonly used in everyday settings—to boil water and convert it to steam, for example. Heating a liquid takes time, however, which makes rapid vaporization difficult. On the other hand, one can also heat the liquid in advance and then abruptly reduce the pressure, as illustrated by the arrow with the solid line Solid line. The pressure in the vaporization section of the injector can be reduced instantaneously, and this makes it possible to vaporize a liquid source instantaneously.

Gas and Liquid Mixture Method

Gas and Liquid Mixture Method

This vaporization method is used in the MI/MV series. Since the pressure of the carrier gas is higher ahead of the nozzle inside the injector, it can be heated efficiently. The liquid source and the heated carrier gas are mixed together in the gas/liquid mixing area just before the nozzle, the pressure is reduced as they pass through the nozzle, which vaporizes the mixture.
Vaporization efficiency is higher than with traditional vaporization methods. When this method is used, larger flows can be generated, and the generation temperature can be reduced.

Optimal vaporization methods for different liquids

In semiconductor devices, which continue to require greater integration and detail, a variety of liquid sources are used to accentuate the characteristics of the films created. HORIBA STEC offers vaporization
systems that are optimized to make the most of the characteristics of the various liquid sources used in today's cutting-edge processes.

Vaporization Model Example