Atomic Layer Deposition

Due to high controllability of deposition parameters (thickness; composition and structure), excellent uniformity and consistency, atomic layer deposition has gained broad applications micro/nanoelectronics and nanomaterials. Below is one of the major applications:

Transistor gate dielectric layer

Conventional vapor, sputtering and chemical vapor deposition techniques are prone to pinholes and interface defect formation. In contrast, atomic layer deposition can ensure good uniformity, reproducibility, low stress, accurate stoichiometry, low defect density in amorphous films. Besides depositing common oxides, this technology can be used in the fabrication of high mobility GaAs/AlGaAs hetero-structure, organic transistors, nanotube devices, etc

Intel and IBM first announced atomic layer deposition high-k gate dielectric based on Hf, which significantly advanced CMOS technology. Intel, early on, used ALD high-k HfO2 gate dieletrics in 45nm processors. Advantages of ALD have become more obvious in Intel's volume production of 32nm processors for addressing challenges related to material volatility, transport and purity.

Advantages of atomic layer deposition: low defect density, controlability of uniformity and thickness, capability of forming thin amorphous coatings.

Applications in this category include HfO2, ZrO2, Al2O3, LaAlO3, GdScO3 and other high-k dielectric films for Si based transistors, GaAs/AlGaAs heterostructure transistors, electron tubes, etc.