High-Field Breakdown and Thermal Characterization of Indium Tin Oxide Transistors
Haotian Su, Yuan-Mau Lee, Tara Peña, Sydney Fultz-Waters, Jimin Kang, Çağıl Köroğlu, Sumaiya Wahid, Christina J. Newcomb, Young Suh Song, H.‐S. Philip Wong, Shan X. Wang, Eric Pop
Abstract
Amorphous oxide semiconductors are gaining interest for logic and memory transistors compatible with low-temperature fabrication. However, their low thermal conductivity and heterogeneous interfaces suggest that their performance may be severely limited by self-heating, especially at higher power and device densities. Here, we investigate the high-field breakdown of ultrathin (∼4 nm) amorphous indium tin oxide (ITO) transistors with scanning thermal microscopy (SThM) and multiphysics simulations. The ITO devices break irreversibly at channel temperatures of ∼180 and ∼340 °C on SiO 2 and HfO 2 substrates, respectively, with failure primarily caused by thermally-induced compressive strain near the device contacts. Combining SThM measurements with simulations allows us to estimate a thermal boundary conductance of 35 ± 12 MWm –2 K –1 for ITO on SiO 2 and 51 ± 14 MWm –2 K –1 for ITO on HfO 2 . The latter also enables significantly higher breakdown power due to better heat dissipation and closer thermal expansion matching. These findings provide insights into the thermo-mechanical limitations of indium-based amorphous oxide transistors, which are important for more reliable and high-performance logic and memory applications.