Film Deposition by Plasma Techniques

Properties of thin films depend strongly upon the deposition technique and conditions chosen. In order to achieve the desired film, optimum deposition conditions have to be found by carrying out experiments in a trial-and­ error fashion with varying parameters. The data obtained on one growth apparatus are often not transferable to another. This is especially true for film deposition processes using a cold plasma because of our poor under­ standing of the mechanisms. Relatively precise studies have been carried out on the role that physical effects play in film formation such as sputter deposition. However, there are many open questions regarding processes that involve chemical reactions, for example, reactive sputter deposition or plasma enhanced chemical vapor deposition. Much further research is re­ quired in order to understand the fundamental deposition processes. A sys­ tematic collection of basic data, some of which may be readily available in other branches of science, for example, reaction cross sections for gases with energetic electrons, is also required. The need for pfasma deposition techniques is felt strongly in industrial applications because these techniques are superior to traditional thin-film deposition techniques in many ways. In fact, plasma deposition techniques have developed rapidly in the semiconductor and electronics industries. Fields of possible application are still expanding. A reliable plasma reactor with an adequate in situ system for monitoring the deposition conditions and film properties must be developed to improve reproducibility and pro­ ductivity at the industrial level.

Contenu

1. The Plasma State.- 1.1 Characterization of Plasma.- 1.1.1 The Temperature of the Plasma.- 1.1.2 Plasma Density.- 1.1.3 Plasma Oscillation.- 1.2 Classification of Plasma.- 1.2.1 Cold Plasma.- 1.2.2 Thermal Plasma.- 2. Reactions in Plasmas.- 2.1 Collision Phenomena.- 2.1.1 Velocity Distribution of Particles.- 2.1.2 Elastic and Inelastic Collisions.- 2.1.3 Collision Frequency and Mean-Free Path.- 2.1.4 Reaction Cross Section.- 2.2 Excitation and Ionization.- 2.2.1 Internal Energy.- 2.2.2 Excitation and Ionization Processes.- 2.2.3 Excitation and Ionization by an Electron Collision.- a) Excitation and Ionization of an Atom.- b) Excitation and Ionization of a Molecule.- 2.2.4 Excitation and Ionization by Collisions of Energetic Ions or Neutral Particles.- a) Thermal Ionization.- b) Penning Ionization.- c) Ionization by Collisions Among Excited Particles.- 2.2.5 Photo-Excitation and Photo-Ionization.- 2.3 Recombination.- 2.3.1 Recombination Processes.- 2.3.2 Ion-Electron Recombination.- 2.3.3 Ion-Ion Recombination.- 2.4 Ion-Molecule Reactions and Reactions Involving Negative Ions.- 2.4.1 Attachment and Detachment.- 2.4.2 Ion-Molecule Reaction.- 2.5 Transport Phenomena.- 2.5.1 Drift.- 2.5.2 Diffusion.- 3. Generation of Cold Plasma.- 3.1 Electrical Breakdown and Starting Voltage.- 3.1.1 Static Electric Field.- 3.1.2 Alternating Electric Field.- 3.2 Glow Discharge.- 3.2.1 General Characteristics.- 3.2.2 Potential Distribution.- 3.2.3 Normal Glow and Abnormal Glow.- 3.2.4 Hollow Cathode Discharge.- 3.3 High-Frequency Discharge.- 3.3.1 Generation of High-Frequency Discharge.- 3.3.2 Potential Distribution and Self-Bias.- 3.3.3 Plasma Potential.- 3.4 Microwave Discharge.- 3.4.1 Generation of Microwave Discharge.- 3.4.2 Electron Cyclotron Resonance.- 4. Plasma Diagnostics.- 4.1 Optical Spectroscopy.- 4.1.1 Optical Emission Spectroscopy.- 4.1.2 Optical Absorption Spectroscopy.- 4.1.3 Laser-Induced Fluorescence Spectroscopy.- 4.1.4 Coherent Anti-Stokes Raman Spectroscopy.- 4.1.5 Optogalvanic Spectroscopy.- 4.2 Probes.- 4.2.1 Langmuir Single Probe.- 4.2.2 Double Probe.- 4.2.3 Emissive Probe.- 4.3 Particle Measurements.- 4.3.1 Mass Spectrometry.- 4.3.2 Energy Analysis of Ions.- 4.4 Others.- 4.4.1 Electron-Spin Resonance.- 4.4.2 Microwave Diagnostics.- 5. Cold Plasma and Thin Film Formation.- 5.1 Interactions of Cold Plasma with Solid Surfaces.- 5.1.1 Adsorption and Trapping.- 5.1.2 Sputtering.- 5.1.3 Secondary-Electron Emission.- 5.1.4 Chemical Reactions on Solid Surfaces.- 5.2 Application of Cold Plasma to Thin Film Deposition.- 5.2.1 Classification of Deposition Processes.- 5.2.2 General Considerations of Plasma Processes.- 6. Physical Vapor Deposition Under Plasma Conditions.- 6.1 Sputter Deposition.- 6.1.1 Features of Sputter Deposition.- 6.1.2 Reactor Configuration.- 6.1.3 Reactive Sputter Deposition.- 6.1.4 Morphology and Characteristics of the Films.- 6.2 Ion Plating.- 6.2.1 Reactor Types and Features.- 6.2.2 Applications of Ion Plating.- 7. Chemical Vapor Deposition Under Plasma Conditions.- 7.1 Plasma-Enhanced Chemical Vapor Deposition.- 7.1.1 Reaction Mechanisms.- 7.1.2 System Design.- 7.1.3 Applications of Plasma Enhanced CVD.- a) Amorphous Silicon.- b) Silicon Nitride.- c) Amorphous and Diamond-Like Carbon.- d) Other Materials.- 7.2 Plasma Polymerization.- 7.2.1 Features of Plasma Polymerization.- 7.2.2 System Design.- 7.2.3 Plasma Polymer.- 7.3 Other Techniques.- 7.3.1 Plasma Stream Transport.- 7.3.2 Chemical Transport in Plasmas.- 7.3.3 Film Deposition Using Electron Cyclotron Resonance Plasma Sources.- 8. Surface Modification by Cold Plasma.- 8.1 Surface Treatment for Metals and Semiconductors.- 8.1.1 Ion Nitriding and Ion Carburizing.- 8.1.2 Plasma Nitriding.- 8.1.3 Plasma Oxidation and Plasma Anodization.- 8.1.4 Hydrogen Neutralization in Semiconductors.- 8.1.5 Other Techniques for Metal Surface Treatment.- 8.2 Modification of Polymer Surfaces.- References.- Further Reading.