Alternative dielectric materials

Thus Ta205 is deposited and the carbon compounds are evacuated [288]. The only disadvantage is that a thick interfacial Si02 layer with a low dielectric constant will be formed during PECVD. 

It was found that for ECR PECVDA, different electrode materials have different incubation periods, which is the time required to cover up the substrate surfaces completely with Ta2Os. Furthermore, the incubation period for the Ta2Os film 

The downscaling limit of Ta2Os capacitors is estimated to be around an equivalent oxide thickness of 1.5 nm [284]. Combined with polysilicon electrode techniques, such as HSG, Ta205 capacitors will be available for 1 Gb DRAMs and beyond. 

Currently, Ta2Os has already reached the stage of practical use and is the most likely choice for replacement of ONO/ON dielectrics after the 256 Mbit generation. 

Si3N4 barrier layer formation by nitridation (thickness below 1 nm). 

---

Multilayer Capacitors. Multilayer capacitors (MLC), at greater than 30 biUion units per year, outnumber any other ferroelectric device in production. Multilayer capacitors consist of alternating layers of dielectric material and metal electrodes, as shown in Figure 7. The reason for this configuration is miniaturization of the capacitor. Capacitance is given by... 

The Parylene family has very attractive properties for use as dielectric materials as was noted above, but their thermal stability at the temperatures used in the fabrication of electronic devices is less than optimum. When considering alternatives as possible precursors for VDP, the isomeric ortho-xylylene (o-quinodimethane) is a likely candidate (Scheme 4). This approach involves the thermolysis ofbenzocyclobutene derivatives to generate a reactive dieneoid intermediate (o-quinodimethane),... 

For synthesis of composite films with M/SC nanoparticles distributed in the volume of a dielectric matrix, method PVD is used as co-deposition of M/ SC and dielectric material vapors. A comparison of films produced by codeposition and layer-by-layer deposition PVD methods has been made on the example of BN-Fe nanocomposite films [57]. Unlike the above considered film from alternating layers of Fe and BN, which has ordered structure, co-deposited BN-Fe nanocomposite films consist of amorphous completely disorder matrix BN containing a chaotic system of immobilized Fe nanoparticles. At the same time, these particles in contrast to those of layered film have much smaller size (d — 2.3 nm) since in this case the metal atoms are inside a matrix which slowdowns the diffusion process of atoms aggregation. 

The application of an alternating electric field causes polarization of dielectrics in the low-freqnency regions of the field. As the frequency increases, the polarization does not follow the changes in the electric field. The dielectric constant of the dielectric materials decreases with the frequency increase by the space charge, dipole, ionic, and/or electronic polarization mechaifisms. The dielectric loss is the maximnm at the dispersed frequencies (f, as shown in Figure 22.2. 

In what follows, the laser damage characteristics are discussed when both alternating current electric fields and ultra-short pulse lasers are simultaneously applied to the dielectric materials. It is true that very high electric fields may allow the electron to reach an energy level sufficient to ionize, causing the impact ionization. As discussed earlier, the damage... 

Loss angle (S) - For a dielectric material in an alternating electromagnetic field, 5 is the phase difference between the current and the potential difference. The function tan 5 is a measure of the ratio of the power dissipated in the dielectric to the power stored. 

Dielectric welding (RF) alternating waves from an electromagnetic generator excite the bipolar molecules of a dielectric material to such an extent that the molecular vibration causes friction between the molecules, which results in the fabric interface melting. In seaming, the fabrics are placed between two electrodes—one live electrode and the other a ground electrode. 

The CPE has also been interpreted as a distribution of relaxation times due to inhomogeneities in dielectric materials, that is, materials that can pass an alternating current but not a dc current. The main problem associated with the CPE is that... 

---