Improved Ferroelectricity and Endurance of Hf0.5Zr0.5O2 Thin Films in Low Thermal Budget with Novel Bottom Electrode Doping Technology

HfO2-based ferroelectric memory is one of the most attractive candidates for embedded memory in future monolithic-M3D integrated-circuit (IC). However, ferroelectricity and endurance will degrade at lower annealing temperatures due to the limitation of the M3D-IC in thermal budget, which significantly inhibits its potential for many applications. In this work, a novel process technology using As5+ implantation (As-imp) at the bottom electrode (BE) in TiN/Hf0.5Zr0.5O2(HZO)/TiN capacitors is proposed. The HZO film shows excellent ferroelectricity and improves endurance at the annealing temperatures of 350 and 400 degrees C, especially when the dose of As-imp is 1 x 10(16), where the endurance of the HZO film is up to 1.5 x 10(11), and the remnant polarization (P-r) far exceeds the reference capacitor without BE As-imp, where 2P(r) is greater than 40 degrees C cm(-2) after 1.5 x 10(11) cycles. The underlying physical mechanism is that the oxidation reaction of introduced As5+ during the film deposition releases extra oxygen atoms to fill the oxygen vacancies (V-o) near the BE interface due to the occurrence of the thermal reduction reaction in the subsequent annealing process. This study paves the way for the integration of HZO-based ferroelectric embedded memory in future high-performance and energy-efficient 3D-ICs.