Silicon Nitride Single Crystals Structure

Three crystallographic modifications of silicon nitride have been identified, namely a, P, and y. In general, it is accepted that a-Si3N4 is the low-temperature 

Cubic 813X4 has the space group Fd3m (Z = 8), and contains both tetrahedrally and octahedrally coordinated silicon atoms with a 1 2 ratio. Thus, the cubic phase may be 

In Nature, an additional mineral, nierite (Si3N4), was found in the perchloric acid-resistant residues of primitive meteorites (ordinary chondrites [29] and enstatite chondrites [30, 31]) [32]. This mineral was seen to occur in lathe-shaped grains that were 2 pm x 0.4 pm in size. An inspection of the mineral by using selected area electron diffraction (SAED) showed the d-spacings of nierite to be comparable to those of synthetic a-Si3N4. The unit-cell parameters of nierite, as calculated from measured d-spadngs, were a = 0.774 0.002 nm, c = 0.561 0.002 nm, while the calculated density was 3.11 gcm [33]. 

---

Silicon nitride-based polycrystalline ceramic materials have the potential for structural applications at both room temperature and elevated temperatures, despite containing silicate/silicate-rich oxynitride grain boundary phases. These are generally much weaker compared to the silicon nitride single crystal grains of which the... 

This type of material is commonly used in the production of semiconductor devices.57 The silica layer is used as a starting layer for integrated circuit (IC) build-up. IC layer materials range from single crystals and doped polycrystalline silicon, silicon nitride, thermally-grown oxide to vapour deposited or sputtered metal or metal silicide layers. Structural adhesion of the various layers is obtained by the application of organosilanes, such as AEAPTS, APTS and GPTS. 

The structure property relationships observed in the Si-N system [17], are reminiscent of those observed for silicon nitride whiskers grown by metal catalyzed chemical vapor deposition (Chapter 2.2). The difficulty in obtaining binary (i.e., boron or silicon nitride) fibers with exactly required stoichiometry seems to have so far precluded the production of single crystal fibers by this route. 

The triaminosilane 2 is somewhat air- and moisture-sensitive but can be stored indefinitely in an inert atmosphere. Minor deviations in the elemental analysis data are due to the formation of silicon carbide and silicon nitride. It is highly soluble in common organic solvents. The solid-state structure of 2 has been determined by single-crystal X-ray analysis and shows nitrogen-hydrogen bridges. ... 

---