A group of dielectric compounds and mixtures of dielectric compounds with useful properties at microwave frequencies is disclosed. The dielectric materials are temperature compensated, have relatively high dielectric constants, and comprise the group of BaTi.sub.4 O.sub.9, and mixtures of Li.sub.2 TiO.sub.3 and Li.sub.4 Ti.sub.5 O.sub.12, MgTi.sub.2 O.sub.5 and TiO.sub.2, Zn.sub.2 TiO.sub.4 and TiO.sub.2, and BaTi.sub.4 O.sub.9 and TiO.sub.2.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation of application Ser. No. 385,017, filed Aug. 2, 1973 now abandoned, which is a continuation of application Ser. No. 130,356 filed Apr. 1, 1971 (now abandoned).
A process is described for the preparation of ceramic dielectrics for microwave applications which yield high quality (Q) factors, high dielectric stability and excellent mechanical stability. The procedure is particularly useful where the size of the ceramic dielectric structures is large (average diameter greater than one inch).
A ceramic anode composition is formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The anode is prepared as a non-stoichiometric crystalline structure by reaction and conditioning in a hydrogen gas cover containing minor proportions of carbon dioxide and water vapor. The structure exhibits a single phase and substantially enhanced electrical conductivity over that of the corresponding stoichiometric structure. Unexpectedly, such oxides and oxygenates are found to be stable in the reducing anode fuel gas of a molten carbonate fuel cell.
High dielectric constant capacitors and/or inductors are formed on a substrate by depositing an amorphous layer (10) of a metal oxide on the substrate (12). A pattern is formed in the metal oxide by wet or dry etching to remove portions (17) of the amorphous material so that only portions (18) of the substrate remain covered. This pattern subsequently becomes the dielectric portion of the capacitor or the inductor. The patterned amorphous layer of metal oxide is then heated under conditions sufficient to convert it from amorphous to crystalline (16), thus increasing the dielectric constant.
The present invention provides a dielectric material adapted for microwave integrated circuits (MIC) and an electric circuit making use of said dielectric material. More particularly, an oxide dielectric material principally consisting of (1-x)BaO.xTiO.sub.2 (0.7.ltoreq.x.ltoreq.0.95) and containing both 0.007 to 0.7 weight % of manganese and 0.037 to 3.7 weight % of zirconium, has a large dielectric constant, a small dielectric loss and a small temperature coefficient of dielectric constant and is uniform over a broad range, and especially it is possible to easily manufacture a substrate having a uniform dielectric constant and a uniform dielectric loss. Transistors and MIC's employing such substrates can attain uniform and excellent high-frequency characteristics.
Revitalization of air by circulation thereof through a quantity of a salt zirconium, titanium or boron and oxygen in the peroxide or higher positive valence state and by mixtures thereof with an alkali metal or alkaline earth hydroxide, oxide, peroxide, superoxide, or ozonide or mixture thereof.
