Michio Ohue

Reactive Ion Etching of Sputtered PbZr1-xTixO3 Thin Films

Reactive ion etching (RIE) by CCl4 plasma of sputtered PbZr1-xTixO3 (PZT) thin film has been investigated. The etching rate of the as-deposited pyrochlore phase PZT is comparable to that of perovskite which was crystallized by 600°C annealing. Etching rate increased with increasing RF power and reached a plateau at 1.0 W/cm2. Highly anisotropic etching of PZT with little resist damage could be realized by reducing RF power.

Effects of Excited Plasma Species on Silicon Oxide Films Formed by Microwave Plasma CVD

By using a microwave plasma deposition system, effects of highly excited plasma species on the film formation of silicon oxide have been studied and the roles of excited ion and radical species have been investigated by emission spectra of the excited plasma species. A strong correlation was confirmed between film quality and the amount of highly excited ion species transported to the substrate. Furthermore, high quality films could be formed by increasing the amount of the excited species.

Effects of Excited Species in Electron Cyclotron Resonance Plasma on SiN Film Resistivity

Optical emission spectra were measured and the relationship between resistivity of SiN films which were deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) and emission intensities from species excited by electron cyclotron resonance was clarified. With increasing microwave power of lowered reacting pressure or SiH4 gas flow rate, the light intensity from excited ions increased in comparison to the intensity from excited radicals. As a result of increasing excited ion density, the SiN film was condensed and the prismatic structure observed in low-resistivity film was not absent from high-resistivity film.

Effects of Applied Magnetic Fields on Silicon Oxide Films Formed by Microwave Plasma CVD

By using a microwave plasma deposition system in which distributions of applied magnetic fields can be varied, the effects of the ECR position and plasma species on deposition rate and deposited film quality of silicon oxide are studied. The following results are obtained: deposition rate increases when not only O2 but also SiH4 as a material gas are excited by ECR, and high-quality film equivalent to thermal SiO2 film can be formed when the ECR position is located close to the substrate. It is suggested that the process of forming high-quality film is related to highly excited ions transported to the substrate.

High-Quality, High-Rate SiO2 and SiN Films Formed by 400 kHz Bias Electron Cyclotron Resonance-Chemical Vapor Deposition

A new electron cyclotron resonance (ECR) plasma CVD system is proposed to form high-quality SiO2 and SiN films at high rates. The system applies 400 kHz voltages which ions can follow to the substrate. The system efficiently produces, without heating: 1) SiO2 films in which density and Si-O bond strength are equivalent to those of a thermally oxidized (about 1000° C) film for which deposition rate is higher than 1.2 µ m/min and 2) Si-H bond-free SiN films in which density and resistivity are higher than those of films formed by conventional plasma CVD systems and for which deposition rate is higher than 0.8 µ m/min.

Planarized SiO/sub 2/ formation by a new microwave plasma system

An improved microwave plasma system is proposed to form planarized SiO/sub 2/ interlayers for LSIs. A high planarization rate was achieved by controlling the formation of a cylindrical plasma and by adjusting the frequency applied to the substrate by which ions can be impinged onto the substrate at a maximum speed. Electric damage was decreased by using oxygen ion sputtering and by suppressing the stimulated bias voltage. These features ensure that a low-damage, planarized SiO/sub 2/ film is formed at a rate of more than 200 nm/min without a stimulated bias voltage.<<ETX>>