Investigation of In-Sn-Zn Composition on the Characterization of Submicron Channel Length Ultra-Thin Atomic Layer Deposited InSnZnO Channel Transistors

The study focuses on developing ultrathin 3 nm-thick indium-tin-zinc-oxide (ITZO) films for submicron channel length thin-film transistors (TFT) using atomic layer deposition (ALD). We aimed to enhance the performance and thermal stability of TFTs by optimizing the ITZO channel composition with a low thermal budget (250 °C). The optimized TFTs with the In
0.6
Sn
0.2
Zn
0.2
O channel demonstrated high performance with a threshold voltage (V
th
) of 0.56 V, field-effect mobility (μ
FE
) of 36 cm
²
/V·s, a subthreshold swing (SS) of 78 mV/dec, a low drain-induced barrier lowering (DIBL) of 88 mV/V, and an I
ON
/I
OFF
ratio of over 10
⁹
. Notably, the devices with the In
0.6
Sn
0.2
Zn
0.2
O channel exhibited exceptional thermal stability under positive bias temperature stress (PBTS) at 85 °C, resulting in a minimal V
th
shift of ~0.18 V at 85 °C. This study underscores the potential of ultrathin ALD ITZO films as viable candidates for BEOL-compatible transistors in monolithic 3-D (M3D) integration, offering significant advancements in the performance and durability of TFTs.