The properties of mfmos one transistor memory devices

Abstract

Integration processes for one transistor memory device have been optimized to reduce process-induced damages. One-transistor ferroelectric memory devices with MOCVD Pb5Ge3O11 (PGO) MFMOS memory cells have been fabricated. The hysteresis loop of a 300 nm thick PGO thin film capacitor exhibited a square and saturated form with 2Pr of about 4 μC/cm2 and 2Ec of 134 KV/cm at an applied voltage of 5V. The capacitor leakage current is 1– 5 × 10−7 A/cm2 at 100KV/cm. The peak dielectric constant is around to 35 – 45. The c-axis oriented Pb5Ge3O11 thin film also showed very good retention properties. The 1T-memory devices showed memory windows around 2V. The memory windows were almost saturated when the operation voltage is 2V. After programming to -4 V (on “off'’ state), the drain current (Id) of the memory transistor operated at Vd of 0.1V and Vg of 0.5 V is about 1×10−8 A. After programming to 4V (on “on” state) the drain current (ID) of the device operated at VD of 0.1V and VG of 0.5 V is about 1 ×10−6 A, which is about 100 times high than that of “off state. The device also exhibits excellent imprint and fatigue properties.