Technologieentwicklung und Herstellung von SiC-basierten (V)UV-Photodioden mit Ionenimplantierten p-Emitter
Third Party Funds Group - Sub project
Start date : 01.01.2020
End date : 31.12.2021
Extension date: 31.05.2022
Project details
Short description
Sensors for UV radiation based on the semiconductor material silicon carbide (SiC) will be developed. These are supposed to allow the detection of UV radiation with particularly short wavelengths (Vacuum-UV). This has not been able with current SiC based sensors yet. Therefore, the present manufacturing process has to be modified and enhanced, so that the electrically active area reaches close to the sensor surface while maintaining a sufficiently high sensitivity. Besides that, new design types of the sensor are considered in order to improve the sensitivity. Device simulation supports the process development and the results of the experiments will be used to enhance the simulation models as well.
Scientific Abstract
A new manufacturing method for SiC-based (V)UV-photodiodes with an ion implanted emitter will be developed. Photodiodes with a sensitivity for wavelengths below 200 nm (Vacuum-UV) are of special interest. Therefore, a shallow p-emitter is necessary, whose manufacturing process based on an ion implantation of Aluminum will be investigated. Perfectly fitted implantation energies, doses, angles and stay oxide thicknesses shall reduce the occurring channeling effect in SiC and lead to a low emitter depth. Simultaneously, the diffusion behavior of shallow Aluminum doping profiles will be studied. The occurring crystallographic damage due to the ion implantation shall be recovered and annealed. In this context, the used process steps will be optimized and may be supplemented with additional measures in order to enhance the carrier lifetime especially in the near-surface depletion region. The high temperature process used for the annealing and the activation of Aluminum can produce carbon vacancies. Since these may act as recombination centers and worsen the carrier lifetime, new methods to minimize the carbon vacancies will be considered. The different process options oxidation and TEOS deposition to build up the SiO2 anti-reflective layer will be compared. In this context, the homogeneity of the sensitivity over the wafer and the impact on the interface defect density are the main focus. Additionally, different design variation will be analyzed, e.g. a finger structure for contacting the emitter, with the aim of reducing potentially high series resistances of a shallow emitter. Analytical and numerical device simulation are used to support the dimensioning and the results of the experiments will allow an enhancement of the simulation models.
