DLI stands for Direct Liquid Injection.
This is a vaporization technology that has been primarily developed to vaporize chemical precursor with a low vapor pressure.
Direct Liquid Injection
In the direct liquid injection the precursor container and the vaporizer are two separated parts. The precursor container always remains at room temperature. The vaporizer is heated and the carrier gas flow is delivered in the vaporizer with the liquid or solution flow.
The quantity of liquid or solution injected/delivered per unit time in the vaporizer is only what is required per unit time for the process. The chemical precursor remains at room temperature as long as it is not required to be vaporized for the process.
DLI vaporizers can handle both liquid and solid ALD and CVD precursors. Solid precursors need to be dissolved in an organic solvent. The technology is a particularly well suited method for low vapor pressure and poorly thermally stable liquid or solid ALD and CVD precursors. Advantages of DLI:
- Precise measurement and control of the precursor quantity injected in the vaporizer per unit time and by consequence precise control of the vapor flow that is generated
- Fast vapor flow ON and vapor flow OFF
- Capability to operate under vacuum or at atmospheric pressure
- Precursor container remains at room temperature: no precursor thermal decomposition overtime, no safety issue, easy and quick container refill/replacement
- Best approach to generate stable vapors flow when solid precursor is used
- Best approach to vaporize low vapor precursors and thermally sensitive precursor while minimizing precursor thermal decomposition
- Accurate control of doping levels
- Capability to vaporize high flows of liquid precursors (organometallic and organic ones) that are significantly volatile such as for instance TMA (trimethyl aluminum), DEZ (diethyl zinc)…