High-Temperature\nStable Amorphous Sn-Rich InSnGaO\nThin Films Fabricated Via Atomic Layer Deposition for Next-Generation\nDynamic Random-Access Memory Applications

Facile\nphase transitions and electrical degradation of amorphous\noxide semiconductors due to a high thermal budget have significantly\nlimited their dynamic random-access memory (DRAM) applications, which\nrequire high thermal stability at temperatures over 600 °C. In\nthis paper, we report an amorphous In–Sn–Ga–O\n(ITGO) semiconductor fabricated via atomic layer deposition, which\nexhibits high-temperature (∼700 °C) phase stability with\nmoderate electrical properties. The optimal Sn-rich ITGO composition\n(In/Sn/Ga = 25:58:17 at. %) represents a thermally stable amorphous\nphase with excellent Hall mobility (24.0 cm<sup>2</sup>/(V s)) above\n600 °C. Various analytical and simulation methods reveal the\nrole of Sn as an efficient amorphous stabilizer and enhancer of electron\nmobility in oxide semiconductors. A thin-film transistor with a 4.5\nnm-thick ITGO channel demonstrates excellent field-effect mobility\n(7.7 cm<sup>2</sup>/(V s)) and reliability. Therefore, Sn-rich ITGO\nis a promising candidate for next-generation DRAM channels that require\namorphous-phase stability at a high thermal budget.