Search

In this work we report on the magnetron reactive ion etch (MRIE) technology for gallium nitride (GaN) and aluminum gallium nitride (AlxGa1-xN) using dichlorodifluoromethane (CCl2F2), commonly known as halocarbon 12, with etch rates greater than 1,000 and 840 Å/min, respectively. Magnetic confinement of a very low pressure (10-4 Torr range) radio frequency (RF) discharge generates high-density plasmas, with low sheath voltages at the bounding surfaces, and very high dissociation of the source gas. Furthermore, the very low pressure of the etch process is characterized by long mean free paths so that sputtering contamination is reduced. MRIE chemistry has been monitored in situ by means of mass spectroscopy. Finally, we report on the successful fabrication of an indium gallium nitride (InxGa1-xN) blue light emitting diode (LED), whose fabrication sequence included the MRIE etching of GaN in CCl2F2. [ABSTRACT FROM AUTHOR]

The way of obtaining the Schrödinger equation for a quantum particle in an electromagnetic field is revisited, showing that very few physical assumptions are required. In fact, after having introduced the general formalism of non-relativistic quantum mechanics, it is shown that the structure of the Schrödinger equation for a spinless particle is obtained merely by requiring continuity of space and time, and covariance with respect to Galilean transformations. Both the Correspondence and Uncertainty principles then become «theorems». [ABSTRACT FROM AUTHOR]

The paper presents a thermodynamic derivation of the most general expressions for the force density, the electromagnetic surface traction, and the polarization work in an electrically or magnetically polarized solid, which is totally based on a continuum description. The notion of internal stress in polarized materials is discussed. [ABSTRACT FROM AUTHOR]

A phenomenological model which represents a possible alternative to the well-known Preisach's model of magnetic hysteresis is here presented. The main feature of the proposed model, which differentiates it from Preisach's one, is that the individual elementary «particles» are not themselves hysteretic; it is the mechanism by which the state of these particles is modified that introduces hysteretic behaviour. The model appears to be computationally less cumbersome than Preisach's one, while having the same application range. [ABSTRACT FROM AUTHOR]

The classical equations of thermodynamics are here rewritten in the form of a field equation in the n-dimensional space of the state variables. This result is obtained by proving the validity of a theorem for Pfaffian forms in n-dimensional spaces. By using the field expression thus obtained, it becomes possible to reformulate classical thermodynamics in a very compact way. [ABSTRACT FROM AUTHOR]