High-Performance In₂O₃-Based 1T1R FET for BEOL Memory Application

In this article, we report high-performance one-transistor-one-resistor (1T1R) FETs for nonvolatile memory application based on nanometer-thick indium oxide (In
₂
O
₃
) as channel material deposited by atomic layer deposition (ALD). ALD grown hafnium oxide (HfO
₂
) and aluminum oxide (Al
₂
O
₃
) are used as gate dielectrics as well as insulator in resistive part. Two nonvolatile states with different threshold voltages are realized. High I
_{\scriptscriptstyle ON}
/I
_{\scriptscriptstyle OFF}
> 10
¹⁰
at V
_GS
= 0 V, large memory window (MW) exceeding 10 V, and deep sub-60-mV/dec subthreshold slope (SS) are achieved on ALD In
₂
O
₃
1T1R FETs. Channel length ( L
_ch
) and channel thickness ( T
_ch
) dependence of device properties are systematically investigated. Optimized In
₂
O
₃
thickness is determined to 1.2 nm, balancing I
_{\scriptscriptstyle ON}
/I
_{\scriptscriptstyle OFF}
, MW, device variation, and stability. The fabrication process has a low thermal budget below 225 °C. Thus, these 1T1R FETs are back-end-of-line (BEOL) compatible and promising for monolithic 3-D integration to realize near-/in-memory computing.