Growth Of Pillars Research Articles

Etching mechanism of a GaN/InGaN/GaN heterostructure in Cl2- and CH4-based inductively coupled plasmas

The etching mechanism of a GaN/InGaN/GaN heterostructure was studied using Cl2- and CH4-based inductively coupled plasma. The Cl2-based plasmas are effective for fast and smooth etching of the homogeneous GaN layer. However, when the layer has a heterogeneous structure of GaN/InGaN/GaN, Cl2-based plasmas cause many pits or pillars on the surface due to a micromasking effect of low volatile In chlorides. The growth of pillars was accompanied by microtrenching at the bottom of each pillar, which transformed into pits after the pillars were detached from their sites. By adding CH4 gas to the Cl2 plasma, the formation of pillars or pits was reduced, and very smooth surface morphology was demonstrated at the gas condition of 35Cl2+20CH4+5Ar (sccm).

Controlled growth of periodic pillars by glancing angle deposition

It has been shown that glancing angle deposition (GLAD) coupled with a prefabricated seed layer can be used to fabricate periodic microstructures. In this article, we show that the column competition effects inherent within aperiodic GLAD films can be delayed in periodic films due to the tendency of the film to achieve a preferred density at a given flux incidence angle. This technique, coupled with the use of the three-dimensional ballistic simulator, may allow for the design and use of periodic GLAD microstructures in such applications as magnetic pillars and three-dimensional photonic crystals.

Observations of the microscopic growth mechanism of pillars and helices formed by glancing-angle thin-film deposition

We have studied the mechanisms influencing growth of thin films onto an oblique rotating substrate by cross-sectional transmission electron microscopy and scanning electron microscopy. We have analyzed the growth of pillars and helices in random and regular arrays, and have examined the influence of introducing a line of missing nuclei on the growth of regular array of pillars and helices.

Instability, intermittency, and multiscaling in discrete growth models of kinetic roughening

We show by numerical simulations that discretized versions of commonly studied continuum nonlinear growth equations (such as the Kardar-Parisi-Zhang equation and the Lai-Das Sarma equation) and related atomistic models of epitaxial growth have a generic instability in which isolated pillars (or grooves) on an otherwise flat interface grow in time when their height (or depth) exceeds a critical value. Depending on the details of the model, the instability found in the discretized version may or may not be present in the truly continuum growth equation, indicating that the behavior of discretized nonlinear growth equations may be very different from that of their continuum counterparts. This instability can be controlled either by the introduction of higher-order nonlinear terms with appropriate coefficients or by restricting the growth of pillars (or grooves) by other means. A number of such ``controlled instability'' models are studied by simulation. For appropriate choice of the parameters used for controlling the instability, these models exhibit intermittent behavior, characterized by multiexponent scaling of height fluctuations, over the time interval during which the instability is active. The behavior found in this regime is very similar to the ``turbulent'' behavior observed in recent simulations of several one- and two-dimensional atomistic models of epitaxial growth. [pacs{61.50.Cj, 68.55.Bd, 05.70.Ln, 64.60.Ht}]

Case of New Growth of Tonsil and Faucial Pillars, with Microscopic Specimen

Case of New Growth of Tonsil and Faucial Pillars, with Microscopic Specimen