The new technology could entirely replace low temperature polysilicon (LTPS) which is a process central to the manufacture of thin-film transistors (TFTs) used in AMOLED displays, LCD displays, and micro-LEDs. The non-laser technology can be applied to very large substrates for generation 10.5 displays or to microLEDs (only 50µm x 50µm).
The electron mobility reported in the ST paper is higher than those typically reported for both LTPS and IGZO, (indium gallium zinc oxide) which is another contender to replace LTPS. The new eutectic enhanced recrystallization process can take place at temperatures as low at 232°C, when using tin as the metal with silicon, or even lower, and is sharply different from MIC (metal induced crystallization) because there is no metal residue left in the silicon film and the insulator layer is crystalline which allows for heterogeneous nucleation of silicon. In the near future ST will make samples using its newly patented insulator layer made of highly oriented "textured" MgO crystals which should lead to even higher mobility. A modified LTPS – in which a-Si:H is laser annealed (ELA) on the crystalline MgO insulator to improve the mobility of the Si film -- will also soon be reported on.
MgO is also known to lower the leakage current to less than that of SiO2.
The ST technology reported on in the paper was recently patented (see US patents 9,054,249 B2; US 9,722,130 B2; US 8,916, 455 B2; and US 9,856,578 B2).
The high mobility films reported on in the paper are also a promising indicator of strong solar cell performance.
All told, ST display technologies promise to offer emissive, high luminance, and high efficiency devices.
The technology was invented by the late Dr. Praveen Chaudhari, renowned materials physicist, and recipient of the US National Medal of Technology, Ashok Chaudhari, CEO of Solar-Tectic LLC, and Dr. RD Vispute of Blue Wave Semiconductors, Inc. (USA). Characterizations of the samples reported on in the paper were performed at Binghamton University (CASP).
Solar-Tectic LLC specializes in high quality inexpensive thin-film solutions for the solar, display, and glass industries. ST is planning to start a pilot line soon to deliver specific supply components to the industries mentioned.
For licensing, investment, or general inquiries, please contact H. Thomas Davis, Jr. of Carter Ledyard & Milburn LLP [email protected]