ALD Chemistries

A recent addition to the family of hi-tech coatings available through Thin Film Partners LLC, Atomic Layer Deposition (ALD) is an enabling technology that allows us to provision our customer applications in micro-electronics, semiconductors, photovoltaics, biotechnology, LED, optics and fuel cell systems with an advanced nano-scale conformal coating.

  • ALD platforms and associated hardware (Worldwide)
  • Technical instruction and ongoing service/support (Worldwide)
  • ALD Coating services (USA)

ALD belongs to the family of chemical vapor deposition methods (CVD) and was initially developed for manufacturing Nano-laminate insulators ( Al2O3/TiO2) and zinc sulfide (ZnS) phosphor films for thin film electroluminescent displays (TFEL). The unique properties of the coatings, together with the high repeatability, were the main factors leading to successful industrial production. ALD is a mature technology and widely used in an array of commercial applications.

ALD principally deposits metal oxide ceramic films. These films range in composition from the most basic and widely used aluminum oxide (Al2O3), titanium oxide (TiO2) all the way to mixed metal oxide multilayered or doped systems. The degree of design potential is one of the major advantages of this technique as compared to other coating methods.

Gases are used to grow the films onto the substrate. The gases have extremely easy access to the surfaces, even over highly patterned or porous materials. Film thickness control provides for highly conformal and dense films at extremely thin layers (1-100nm).

These ultra-thin films can be grown onto virtually any substrate. ALD films have been demonstrated on highly patterned wafers, polymer films, and fine powders of most compositions. The films deposit as well on single composition materials as they do on multi material composition objects or materials.

TFP CVD as a Low-cost Alternative Protective Coating from Thin Film Partners on Vimeo.

More About ALD

ALD is a deposition process initiated at a nano-scale level, one which results in the formation of ultra-thin films (atomic layers) comprised of a wide variety of chemistries. Going beyond the capabilities of PVD (sputtering) and CVD and parylene chemistries, some of ALD’s more distinct advantages are:

  • ALD processes are self limiting – Unlike parylene, which is a deposition sequence that is “source controlled”, ALD is “surface controlled”. This means simply that parylene deposition is wholly dependent upon feedstock (dimer) and will deposit successive polymer layers until expending the supply. ALD, however, is more controlled. In this process, layers are formed one at a time, until the surface is completely covered. Successive layers are deposited only after a nucleus initiates the subsequent cycle.

  • ALD is extremely conformal – A typical aspect ratio for one parylene variant is 40:1, and the film is delivered in incrementally decreasing thickness as it travels through the entry point of a confined space. In contrast, some ALD coatings can deliver aspect ratios in the range of 5,000:1 or higher, depositing a layer that is uniform from end to end. This feature makes ALD a highly desirable technology in coating any complex geometry - MEMS, nano-scale pores, tubes,  microfluidics/channels, particles, etc.

  • ALD is pinhole-free at nanometer thickness – Parylene and some other chemistries are technically pinhole-free at micron levels while ALD films can be pinhole-free at a sub-nanometer thickness. Certain ALD materials are often deposited over the surface of other coatings to fill the pinholes.

  • ALD accommodates layers or laminates – Most films are single component layers, including parylene. Materials deposited via ALD platforms can be arranged in alternating layers of multiple chemistries.

What are some ALD surfaces?

A wide variety of chemistries are possible with Atomic Layer Deposition:

  1. Oxides
  2. Nitrides
  3. Metals
  4. Carbides
  5. Sulfides

A very wide variety of materials are possible with Atomic Layer Deposition ALD:

  • Oxides, including: Al2O3, CaO, CuO, Er2O3, Ga2O3, HfO2, La2O3, MgO, Nb2O5, Sc2O3, SiO2, Ta2O5, TiO2, VXOY, Y2O3, Yb2O3, ZnO, ZrO2, etc.
  • Nitrides, including Titanium nitride (TiN), Niobium nitride (NbN), Tantalum nitride (TaN), Halfnium nitride (HfN)
  • Metals: Ir, Pd, Pt, Ru, more
  • Carbides: TaC, TiC…more
  • Sulfides: ZnS, SrS, more

Our ALD Expertise

Our ALD experts have more than 50 years of combined experience developing specific surface coatings to precisely meet customer needs/expectations. The team is made of chemists, engineers, and equipment designers to provide a multi-disciplinary view of the problem being solved. This combination of experience and perspective can bring about rapid prototyping as well quick production ready solutions.