No abstract

No abstract

A 0.18-m system LSI embedded ferroelectric memory (FeRAM) operating at a very low voltage has been developed for the first time. The low-voltage operation has been attained by newly developed stacked ferroelectric capacitors completely encapsulated by hydrogen barriers, which enable us to eliminate hydrogen reduction of the ferroelectric thin film during the back end of the line process including FSG, tungsten CVD (W-CVD), and plasma CVD SiN (p-SiN) passivation. A fabricated 1-Mbit one-transistor one-capacitor SrBi 2 (Ta x Nb 1 x ) 2 O 9 (SBTN)-based embedded FeRAM operates at a low voltage of 1.1 V and ensures the endurance cycles up to 10 12 at 85 C and the data retention time up to 1000 h at 125 C, which is the most promising for mass production of 0.18-m low-power system LSI-embedded FeRAM and beyond.Index Terms-Ferroelectric memory, hydrogen barrier, low-voltage operation, reliability.

Changes in the electrical properties of poled ferroelectric SrBi 2 (Ta,Nb) 2 O 9 (SBTN) thin-film capacitors caused by hightemperature storage were studied. Current-voltage (J-V) characteristics of SBTN capacitors before and after high-temperature storage indicated that the current in SBTN is predominantly carried by electrons and limited by electrode interfaces. The voltage shift in the polarization-voltage (P-V) curve caused at high temperatures was ascribed to a bulk effect because there were no definite changes in the interface-limited J-V characteristics before and after high-temperature storage. Assuming the pinning of domains by capturing electrons emitted from traps distributed in the energy gap, we describe the decay in switchable polarization with the power of time. The activation energy for the decay in switchable polarization associated with electron capture was determined to be 0.23 eV based on the temperature dependence of the decay in switchable polarization.

GaAs microwave monolithic integrated circuits (MMICs) with Bal-xSrxTiOs (BST) capacitors have been developed. Spin-coating of sol-gel solution was used to make the BST thin film. The obtained BST film has a dielectric constant of 300 that is 50 times higher than the conventional SiN one. The capacitance has the frequency roll-off over 2 GHz, which is sufficient enough for a variety of consumer applications. The implemented GaAs MMlCs with on-chip BST capacitors enable the positive-bias supply and high gain performance as well as the small package outline.