Nucleation and growth of Ni-LIGA layers

Abstract

The quality of a Ni-LIGA layer and its adhesion to TiO 2 depend crucially on interface morphology and chemistry. The unique combination of ARXPS (angle resolved photo electron spectroscopy), STM (Scanning tunnel microscopy) and DTS (distance tunnel spectroscopy) yield new insights in morphology and stoichiometry on the porous TiO 2 plating ground, on the TiO 2\x (OH) y NiO z Ni interface, and on the Ni-nucleation and growth. Aside TiO 2 -pore dimension, we identified graphite hillocks, with retarded Ni coverage, the adhesion promoting interface oxide TiO 2\x (OH) y Ni z and the Ni nuclei and their expansion.

Fatigue of LIGA Ni Micro-Electro-Mechanical System Thin Films

“…The YoungÕs modulus of the 270-lm-thick film was determined to be~170 GPa. This is comparable to prior reports by Cho et al, [5] Mazza et al, [15] Hemker and Last, [9] Lou et al, [26] Xie et al, [27] and Sharpe et al, [41] as shown in Table I. For the 0.2 pct offset yield stress and ultimate tensile strength, the reported values for LIGA Ni thin films are much larger than those of bulk Ni.…”

An investigation of fatigue in LIGA Ni MEMS thin films

“…In recent years, LIGA Ni micro-electro-mechanical systems (MEMS) structures have been developed for applications in high aspect ratio and thicker devices [1,2] (LIGA is the German acronym for the Lithographic, Galvaroformung, Abformung process). These include: accelerometers for the deployment of airbags [1], weapons safety and arming systems [3], heat exchangers [1] and micro-gears [1].…”

An Experimental Study of Fracture of LIGA Ni Micro-Electro-Mechanical Systems Thin Films

“…[3,4] The applicability of the J-integral [5] for characterizing the near-tip stress and strain fields of a mode I crack in a thin sheet has been demonstrated via three-dimensional finite-element analyses by a number of studies. [6,7,8] In a recent article, Li and Siegmund [9] summarized the range of applicability and limitations of the use of the stress intensity factor K, the J-integral, or its two-parameter (J-Q) extension for predicting the onset of crack growth in thin-sheet structures.…”