Metal Cation Chemistry and Amorphous Structure Governing Hydrogen Tolerance in Oxide Semiconductor Channels for 3D DRAM

This study analyzed hydrogen tolerance in oxide semiconductors subjected to high‐temperature H 2 annealing (400–600°C), considering different metal species and crystallinities. First, various amorphous ternary oxides with fixed 1:1 at.% cation ratios were evaluated to isolate elemental effects; in the order Zn, Ga, In, and Sn, thickness retention improved while variations in carrier concentration ( n e ) and Hall mobility ( µ Hall ) decreased. Next, ternary oxide films with identical compositions were tuned by pre‐annealing temperature to obtain crystalline or amorphous phase; the crystalline films exhibited enhanced etching and larger changes in n e and µ Hall that are consistent with grain boundary effects. Guided by these observations, amorphous In–Sn–Ga–O (ITGO) was benchmarked against conventional In–Ga–Zn–O (IGZO). The ITGO film maintained a thickness change below 1% with limited Hall variation after H 2 annealing at 600°C. By contrast, the IGZO film exhibited an abrupt increase in n e exceeding three orders of magnitude after H 2 annealing at 500°C, then exhibited etching at 600°C. The application of ITGO in a field‐effect transistor preserved switching characteristics after H 2 annealing up to 600°C, indicating its potential as a channel material for dynamic random‐access memory compatible with high‐temperature hydrogen thermal budgets.