Oxide collar

Figure 1.69 Top-down view of a DT structure without applying the anisotropic etch. The oxide collar (dark region) and the DT fill can be seen.

Second barrier layer (Si3N4) + DT fill with highly doped polysilicon + planarization by CMP (chemical mechanical polishing) + oxide collar recess as usual. 

Volume 75 concludes with six procedures for the preparation of valuable building blocks. The first, 6,7-DIHYDROCYCLOPENTA-l,3-DIOXIN-5(4H)-ONE, serves as an effective /3-keto vinyl cation equivalent when subjected to reductive and alkylative 1,3-carbonyl transpositions. 3-CYCLOPENTENE-l-CARBOXYLIC ACID, the second procedure in this series, is prepared via the reaction of dimethyl malonate and cis-l,4-dichloro-2-butene, followed by hydrolysis and decarboxylation. The use of tetrahaloarenes as diaryne equivalents for the potential construction of molecular belts, collars, and strips is demonstrated with the preparation of anti- and syn-l,4,5,8-TETRAHYDROANTHRACENE 1,4 5,8-DIEPOXIDES. Also of potential interest to the organic materials community is 8,8-DICYANOHEPTAFULVENE, prepared by the condensation of cycloheptatrienylium tetrafluoroborate with bromomalononitrile. The preparation of 2-PHENYL-l-PYRROLINE, an important heterocycle for the synthesis of a variety of alkaloids and pyrroloisoquinoline antidepressants, illustrates the utility of the inexpensive N-vinylpyrrolidin-2-one as an effective 3-aminopropyl carbanion equivalent. The final preparation in Volume 75, cis-4a(S), 8a(R)-PERHYDRO-6(2H)-ISOQUINOLINONES, il lustrates the conversion of quinine via oxidative degradation to meroquinene esters that are subsequently cyclized to N-acylated cis-perhydroisoquinolones and as such represent attractive building blocks now readily available in the pool of chiral substrates. 

Dimethyl 3,5,6-trichloro-2-pyridyl phosphate, known as Fospirate or Dowco 217, is an rnsechcide useful rn anlrllea collars for dogs and cats. The compound 4-aminopyridine, known as Avilrol 100, and 4-nitropyridine-N-oxide, known as Avitrol 200, are useful as bird repellents. 

Baltes, M., O. Collar , P. Van Der Voort, and E. F. Vansant, Synthesis of Supported Transition Metal Oxide Catalysts by the Designed Deposition of Acetylacetonate Complexes , Langmuir (1999), 15, 5841-5. 

In Figure 1.69 an example of a conventional DT top-view is shown (oval shape) after collar oxide formation (black region) and DT fill with a highly doped poly-Si. The thermal oxide formed shows a strong dependence on the crystal orientation of the Si surface. This holds true for all oxidation modes, for example, dry and wet oxidation (in the wet -oxidation mode there is a carefully adjusted addition of FI2O as steam to the oxidation chamber resulting in an increased oxidation rate). This also holds true for... 

Figure 11.15 Molecular switch constructed from a rotaxane. The tetrapyridinium macrocycle collars the uncharged reduced form of TTF (tetrathiafulvalene) in the low conductance state and slides along the molecular chain to the dioxynaphthalene site when the TTF is oxidized to its cationic high conductance state. (Reproduced with permission from J. E. Green et al., Nature 2007, 445, 414.)...

CTO consists of approximately 35-50% fatty acids, 15-55% rosin acids, and 5—35% unsaponifiable and neutral material. CTO can be used right away as a surfactant for oil and gas drilling applications or can previously be oxidized by blowing with air at a temperature of 120-130°C for 24h. It forms water-in-oil emulsions and stabilizes the oil-based drilling mud when pumped at high bottom-hole temperature under pressure through the kelly, drill pipe, drill collars, and drill bit (Figure 3B.11). It is then returned... 

---