Back-gated devices from amorphous GaOx grown by ALD for BEOL integration

In this presentation, we discuss the integration of amorphous GaOx into back-gated transistors. The a-GaOx films (22 -100 nm) were grown by plasma-enhanced atomic layer deposition (PE-ALD). The conductivity of the films was tuned by changing the O2 plasma exposure time during the ALD cycles, which determines the content in oxygen vacancies. Back-gated transistors were fabricated with Al2O3 gate oxide on highly-doped Si substrate, with or without encapsulation of the top surface. The electrical properties of the devices will be discussed. Low sub-threshold swing (~150 mV/dec), on/off ratio >105 and operating drain voltage below 5V were obtained.