Development of MIM/Ta₂O₅ capacitor process for 0.10‐µm DRAM

Abstract

SUMMARYAs the fabrication dimension becomes smaller, it becomes increasingly difficult to ensure storage capacitance for DRAM. For this reason, a capacitor process using high-permittivity insulating films is strongly desired. In the research reported here, an MIM/tantalum pentoxide capacitor process is developed with ruthenium as an electrode material. The ruthenium CVD technique, the use of amorphous tantalum nitride as anti-oxide barrier metal, and a contamination elimination process using periodic acid have been developed. By packaging as 0.13-µm DRAM, capacitance performance equivalent to silica film is realized with a film thickness of 0.8 nm. The process is considered to be applicable to 0.10-µm DRAM.

Stereometric analysis of Ta2O5 thin films

“…Tantalum pentoxide (Ta 2 O 5 ) finds use in many electrical and optical applications. In the electrical field it is often employed as a dielectric insulator in metal-insulator-metal (MIM) or metal-insulatorsemiconductor (MIS) structures [1]. These devices are used for example in scaled-down versions of ultra-large scale integrated devices (ULSI), such as dynamic random access memory cards for computing, or three-dimensional capacitor structures, such as the trenched-type capacitor (TTC) [2].…”

Simultaneous measurements of the thermal optical and linear thermal expansion coefficients of a thin film etalon from the reflection spectra of a super-luminescent diode

“…The reason that Ta 2 O 5 films are chosen in our experiments is because of the fact that Ta 2 O 5 is a new material as far as optical engineering applications are concerned. Although tantala has been widely used for storage capacitors because of its large dielectric constant [2][3][4], more importantly, it has promising potential to be one of the best optical coating materials for near-UV and near-IR antireflection, multilayer filter design and optical thermometric sensing applications [5,6].…”

Efficient Detection of Oxygen Vacancy Double Donors in Capacitors with Ultra-thin Ta2O5 Films for DRAM Applications by Zero-bias Thermally Stimulated Current Spectroscopy

“…Tantalum oxide has demonstrated promise as a high-K dielectric for charge storage in Gb dynamic random access memories (DRAMs) [1]- [2]. For DRAM applications, the two most important requirements are high capacitance, limiting film thickness to < 10 nm, and low leakage current, which may be related to defect states in Ta [3], which will make Ta 2 O 5 a very weakly n-type large bandgap semiconductor, resulting in leakage current.…”