Effect of cage configuration in structural and optical properties of tin films grown by cathodic cage discharge

Abstract

Cathodic cage discharge was developed recently in order to eliminate phenomena as edge effect and overheating, which occurs during conventional processes. In this study, the effect of cage configuration in active species during the deposition process and optical properties of TiN film were studied. TiN compound was chosen because its optical properties are very sensitive to slight variations in microstructure and film thickness, becoming a good monitoring tool in fabrication process control. Cages were made of titanium and have different holes numbers and holes diameter. Electrical efficiency of the system and optical properties of TiN films were strongly influenced by experimental conditions. It was found that with more holes at the top of cage, deposition rate and crystallinity were higher, if compared to cages with a small number of holes at the top. On the other hand, the opposite behavior was observed when more holes were located at the sidewall of cage.

Tribo-mechanical features of nitride coatings and diffusion layers produced by cathodic cage technique on martensitic and supermartensitic stainless steels

“…The sample is electrically isolated from the chamber and remains under a floating potential, settled over a ceramic plate at the bottom of a cathodically polarized conduction cage. As described by Daudt et al [5], an effect of multiple hollow cathodes takes place at the walls of the cage. In such a high potential field, the sputtering of the cage walls and interaction with the nitriding atmosphere produce compounds and/or metallic species, which eventually deposit on the sample´s surface.…”

“…It has been investigated in the last years in different classes of materials such as steels and titanium alloys [3][4][5]. Differently from the conventional plasma nitriding (PN), ionic species do not interact directly with the surface under treatment.…”

“…The thermal energy arriving at the treated surface is provided by irradiation from the sputtered walls [1]. It is important to stress that cage´s composition rules the coating nature, which generally comprises of crystalline phases such as ε-Fe 2-3 N and γ´-Fe 4 N if iron-based materials are used and δ-TiN in the case of titanium-based cathodes [3][4][5].…”

“…CC coatings are especially attractive because of the thickness uniformity, structural and excellent mechanical properties throughout the surface area, eliminating the so-called edge effect, typical of plasma nitriding when the sample is directly polarized [1,5]. Such property draws attention to the use in special materials subjected to mechanical and abrasion environments, as the martensitic and supermartensitic stainless steels.…”

Confinamento de elétrons em um sistema de plasma de tela ativa e geração de potencial flutuante extremo no interior da gaiola catódica

“…Recentemente, seu uso foi estendido para outros tipos de materiais, como a funcionalização superficial de materiais poliméricos e fibras de carbono 1,3-5. Nos tratamento com Gaiola Catódica são minimizados os danos devido à minimização do bombardeamento por íons energéticos do plasma, mantendo as espécies ativas geradas na região luminescente, as quais podem se difundir e reagir com as superfícies das peças dentro da gaiola5. Os efeitos dos parâmetros de tratamento com gaiola catódica, como o tamanho da malha, a distância entre a amostra e a tela, a pressão do gás de trabalho, a composição do gás, a geometria da peça a ser tratada, o potencial aplicado e, mais recentemente, a área aberta da tela, já foram estudados por diferentes autores 3,[6][7][8][9][10][11][12][13][14][15][16][17][18][19] . No entanto, esses estudos se concentraram principalmente nas propriedades das camadas tratadas.…”