We report conformal deposition of both RuO2 electrodes and PbZrxTi1−xO3 (PZT) capacitors in submicron Si trenches through the same in situ liquid source mist processing. The step coverage for the RuO2 electrodes is 75% at 225 °C. After electroding, we deposited Pb(Zr,Ti)O3 thin films and nanotubes using the same apparatus with remanent polarization of ∼15 μC/cm2. The step coverage was 59% on the sidewall and 79% on the bottom wall. Electrical testing showed charge storage (capacitance/trench) was 13±2 pF, with a breakdown voltage of 11.3±0.2 V and dielectric constant ε=166±30. This shows that a single inexpensive processing can produce fully electroded dynamic random access memory trenched capacitors with high aspect ratios and commercial electrical performance.
We focused on inductively coupled plasma and reactive ion etching (ICP–RIE) for etching GaN and tried to fabricate distinctive GaN structures under optimized chemical etching conditions. To determine the optimum chemical etching conditions, the flow rates of Ar and Cl2, ICP power, and chamber pressure were varied in the etching of c-plane GaN layers with stripe patterns. It was determined that the combination of Ar and Cl2 flow rates of 100 sccm, chamber pressure of 7 Pa, and ICP power of 800 W resulted in the most enhanced reaction, yielding distinctive GaN structures such as pillars with inverted mesa structures for c-plane GaN and a semipolar GaN layer with asymmetric inclined sidewalls. The selectivity and etching rate were also investigated.
To gain a flat recess profile with uniform etching depth, dry recess experiment with different inductively coupled plasma (ICP) etching conditions was done on an AlGaN/GaN heterostructure. Trenching effect at the bottom near the sidewall was observed when positive photoresist was utilized and the ICP power was low. The recess profile was improved by adopting SiO2 as the etching mask and increasing the ICP power. GaN metal–oxide–semiconductor field-effect transistors (MOSFETs) on AlGaN/GaN heterostructure with different gate recess conditions were fabricated and characterized. The maximum field-effect mobility of 152.8 cm-2 V-1 s-1 and the minimum interface state density of 1.39×1011 cm-2 eV-1 were obtained from the optimized gate recess condition with ICP power of 100 W, bias power of 20 W and etching mask of SiO2.
We extend our previous formulation of low-energy QCD in terms of an effective lagrangean containing operators of dimensionality d ≤ 6 constructed with pseudoscalars and quark fields, describing physics below the scale of chiral symmetry breaking. We include in this paper the vector and axial-vector channels. We follow closely the Extended Chiral Quark Model approach and consistently work in the large-N c and leading log approximation and take into account the constraints from chiral symmetry and chiral symmetry restoration. The optimal fit of all parameters gives further support to a heavy scalar meson with a mass ∼ 1 GeV and a value of the axial pion-quark coupling constant g A 0.55 to 0.66, depending on some assumptions concerning the Weinberg sum rules.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.