STATIC AND LOW-FREQUENCY NOISE CHARACTERISTICS OF N(+)P JUNCTION DIODES FABRICATED IN DIFFERENT SILICON SUBSTRATES

This paper describes the impact of the starting Si material and therma l pretreatment on the static current-voltage characteristics of n(+)p junction diodes, using a combination of large-area, large-perimeter an d gated diodes. In addition, the low-frequency noise spectrum in forwa rd operation is studied for different p-type substrates. It is shown t hat in Czochralski-grown (Cz) wafers, the starting oxygen concentratio n plays a crucial role: highly precipitated high-oxygen diodes show a large bulk and perimeter leakage current and a high ideality factor m. Near ideal behaviour (m approximate to 1) is found for epitaxial and floating-zone (FZ) grown substrates. The surface generation/recombinat ion properties, however, are marginally affected by the interstitial o xygen content. Simultaneously, a clear impact of the substrate type on the low-frequency noise is observed, especially for high forward curr ents, whereby the lowest noise figures are obtained for epitaxial and FZ wafers. It is demonstrated that in Cz wafers both perimeter (surfac e) and bulk noise sources are active, explaining the higher noise leve l.