Integration Processes and Properties of Pt/Pb5Ge3O11/(Zr, Hf)O2/Si One Transistor Memory Devices

Abstract

AbstractThe basic mechanism for one transistor memory device has been studied. Ferroelectric material, Pb5Ge3O11 (PGO) was selected for MFOS (M: Metal, F: Ferroelectrics, O: oxide, S: silicon) memory transistor fabrication. Processing of one-transistor memory devices dealt with the following issues: decomposition of ferroelectric materials, the etching damage of ferroelectric materials, the forming gas annealing damage of ferroelectric materials, the selective deposition of ferroelectric materials, the alignment for device making processes. The integration processes for one transistor memory device have been optimized to reduce process-induced damages. The gate dielectric material is (Zr, Hf)O2. Extremely high c-axis oriented Pb5Ge3O11 thin films were successfully deposited on high k gate oxide. Memory transistors having 0.6, 3 and 10μm channel length and 10 μm channel width have been fabricated. The memory windows are around 1 - 2V. The memory windows are almost saturated from operation voltage of 4V. After programming at -5V (on “off” state), the drain current (ID) at VD of 1V and VG of 2.5 V is about 1.15 ×10−10A. After programming at 5 V (on “on” state) the drain current (ID) at VD of 1V and VG of 2.5 V is measured about 6.4 ×10−8 A, which was 2.5 order higher than that of “off” state.