Barium Neodymium Titanium Borate Glass‐Based High k Dielectrics

Abstract

A nonconventional high k glass based on BaO·Nd 2 O 3 ·-TiO 2 ·B 2 O 3 , which is combined with typical fillers of Al 2 O 3 and BaTiO 3 , has been investigated for the purpose of generating potential k (dielectric constant)~20 and k~40 dielectric materials as a result of densification at 850°C. Crystallization, densification, and dielectric properties depended strongly on the type and content of the fillers. Glass itself was crystallized mainly with BaTi(BO 3 ) 2 . The Al 2 O 3 filler did not seem to be directly involved in the crystallization process as only non Al-containing crystalline phases, such as NdBO 3 , Nd 2 Ti 4 O 11 , and BaNd 2 Ti 5 O 14 , were observed. On the contrary, the Ba-TiO 3 filler resulted in the crystallization of two phases, BaTi (BO 3 ) 2 and BaNd 2 Ti 5 O 14 . As an example of a promising dielectric candidate, a composite sample consisting of the glass and 30 wt% Al 2 O 3 exhibited k~22 and tan d~0.009 with nearly full densification at 850°C.

Effect of Ti4+ on the structure of nepheline (NaAlSiO4) glass

“…Titania (TiO 2 ) has been found to play a significant role in nearly all glass families, though it is not considered to be a glass-forming oxide on its own. Glass formation for Ti 4+ -containing systems has been reported for the following glass families: alkali silicate (Gan et al, 1996;Hamilton and Cleek, 1958;Henderson and St-Amour, 2004;Limbach et al, 2017;Yarker et al, 1986), alkaline earth silicate (Gan et al, 1996;Henderson and St-Amour, 2004;Limbach et al, 2017), aluminosilicate (Kajiwara, 1988), other silicate based glasses (Peterson and Kurkjian, 1972), borate (Lee et al, 2012), tellurite (Nasu et al, 1990;Sabadel et al, 1997), and phosphate (Fu, 2011;Hoppe et al, 2007), as well as in alkali-titanate glasses without traditional glassforming oxides (Miyaji et al, 1991;Rao, 1964;Sakka et al, 1990;Sakka et al, 1989). For many of these glasses, discerning the local environment of Ti 4+ was a primary feature of the study, and was related to the role of Ti 4+ within the glass network, whether it be a glass-former, glassmodifier, or an intermediate species.…”

Microstructure, Thermal and Mechanical Properties of AlN-MgO Composites Prepared by Spark Plasma Sintering

“…In addition, oxygen-related defects, including the residual oxygen present at the interface, the oxide layer on the AlN surface, and the lattice defects induced by oxygen (substitutions and vacancies), contribute to the reduction of the thermal conductivity through phonon scattering [38][39].…”

BaSi4O6N2 – A Hexacelsian‐Type Layered Oxonitridosilicate

“…BaSi 4 O 6 N 2 was prepared by high-pressure synthesis and represents a previously unknown structure type for nitridoand oxonitridiosilicates, namely that of hexacelsian. As the structural family of hexacelsian comprises a wide range of members, [24][25][26][27][28][29][30][31] which have interesting materials properties, [32][33][34][35][36][37][38][39][40][41][42][43] further investigations concerning luminescence, triboluminescence, and band-gap measurements is a prospective subject of interest. Since nitrido-and oxonitridosilicates exhibit excellent luminescence properties, [15][16][17][18][19] this research field is of particular importance.…”

“…In the literature these nonbranched silicate double layers are well known for the feldspar high-temperature phases MAl 2 Si 2 O 8 (M = Ca, Sr, Ba). [24][25][26][27][28][29][30][31] The structure of BaSi 4 O 6 N 2 consists of layers of vertex-sharing SiO 3 N tetrahedra of the Q 3 -type building double layers of 6er-rings [59] as fundamental building units (FBU), [60] which leads to a degree of condensation of κ = n(Si)/n(O,N) of 0.5 for the [Si 4 O 6 N 2 ] 2substructure ( Figure 2). According to lattice energy calculations (MAPLE) [61][62][63] and Pauling's rule [64] there is a clear ordering of N/O.…”

“…nitrido-and oxonitridosilicates. Hexacelsian, which was originally only the denotation for BaAl 2 Si 2 O 8 , [27] now comprises a whole structural family with a wide range of compositions [24][25][26][27][28][29][30][31] and interesting materials properties (e.g. high oxidation resistance, high melting point, low linear dielectric constant, low coefficient of thermal expansion, and triboluminescence).…”