Dielectric reliability measurement methods: A review

摘要

Reliability of thin dielectric films such as silicon dioxide grown on single crystalline silicon is of great importance for integrated circuits of present and future technologies. For the characterization of the quality of dielectric films. it isessential to have measurement methods available which can give a measure of dielectric reliability in a relatively snort time. Stress biases are usually highly accelerated and cause destructive dielectric breakdown. Testing for dielectric reliability hasbeen performed for more than 30 years, and in that time many different stress methods have been established. This article reviews that most common dielectric reliability measurement methods and gives practical guidelines to the reliability engineer in the field of dielectric characterization. The examples and data shown here are mainly from MOS gate oxides. The aim of this review paper is to emphasize advantages and disadvantages of the various stress methods. Appropriate dielectric stress methods arepointed out for applications such as process development. process characterization. pocess control and screening (burn-in). A broad number of different measurement techniques are described in detail for which the set up of the measurement and its stressparameters are clarified. Suitable dielectric test structures and the determination of the correct voltage and thickness of the dielectric are discussed: they are essential to determine the electric field across the thin film. The identification ofdielectric breakdown and the interpretation and significance of the measurement results are reviewed. A good understanding of the stress method and the various measured parameters is essential to draw correct conclusions for the lifetime of the dielectric at operating conditions. The commonly used. basic analysis techniques for the measurement results are illustrated. Finally. the influence of stress-induced leakage current on the dielectric reliability characterization is discussed and other aspectsrelating to ~ery thin oxides of future technologies are briefly described. The paper also includes a large bibliography of more than 250 references.