Newsroom

Improving ALD-III-V interface quality with Kontrox for drastically enhanced device parameters

Many approach us assuming our proprietary technology - Kontrox - is an alternative thin film deposition method similar to ALD. While Kontrox can potentially replace ALD in specific applications (such as microLEDs), its mechanism is fundamentally different. Instead of adding layers on top of the material, Kontrox allows reconstructing the surface of the semiconductor itself atom by atom, creating a nearly perfect crystalline structure. In most applications, Kontrox is a powerful technique to be combined with ALD for drastically improved quality of the interface between the ALD and III-V material.

HR-TEM images from ALD Al2O3-GaAs(100) interface with and without  Kontrox treatment. The Kontrox-treated structure exhibits unprecedentedly low levels of surface defects and a sharp III-V dielectric interface.
HR-TEM images from ALD Al2O3-GaAs(100) interface. The Kontrox-treated structure (on the right) exhibits unprecedentedly low levels of surface defects and a sharp III-V dielectric interface.

Atomic Layer Deposition, or ALD, is an advanced deposition technique that allows depositing ultra-thin films through repeated exposure to separate precursors. The method provides excellent thickness control and uniformity and enables conformal coating for high-aspect-ratio 3D structures. ALD benefits many applications and is currently considered the industry standard for various semiconductor device fabrication.

While ALD is an excellent method, the quality of the interface between III-V and ALD is not sufficient because of the harmful native oxide of the III-V semiconductor material.

Oxidation-induced defects act as traps for charge carriers, causing changes in the device's operation and stability. Despite the extensive work in the field, various etching and passivation methods have been inefficient in reducing the III-V interface defect density to industrial standards set by today's silicon technology.

Our proprietary method - Kontrox - improves the ALD-III-V interface quality by minimizing the interface defects with highly controlled oxidation of III-V material before growing the thin film with ALD. Kontrox forms a highly crystalline 1-2 monolayers thick oxide layer with record-low surface/interface defect state density. The Kontrox layers have low surface energy, and structures increase act as a natural diffusion barrier for further oxidation of III-V material. The improved interfaces are verified, for example, by dramatic enhancement in the photoluminescence intensity in optoelectronic devices, indicating reduced defect-related non-radiative recombination.