Current-voltage and capacitance-voltage characteristics of cadmium-doped p-silicon Schottky diodes

• Published in: Sensors and actuators. A. Physical. Vol. 331; p. 112957
• Main Authors: Bodunrin, J.O., Oeba, D.A., Moloi, S.J.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.11.2021; Elsevier BV
• Subjects: Cadmium; Cadmium-doping; Capacitance; Capacitance-voltage characteristics; Current; Diodes; Doping; Electrical resistivity; Electrodes; Energy gap; Majority carriers; Minority carriers; Radiation; Radiation damage; Radiation detectors; Radiation tolerance; Resistivity; Schottky diodes; Silicon; Space charge; Schottky diodes; Radiation detectors; Resistivity; Cadmium-doping; Capacitance; Silicon; Current
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2021.112957

Schottky diodes were fabricated on undoped and Cd- doped crystalline n-Si. The diodes were characterized using I–V and C–V techniques to investigate a change in electrical properties of the diodes due to Cd-doping. A change in diode conduction mechanism and diode parameters due to Cd-doping were studied in detail. [Display omitted] •I–V and C–V behaviour of undoped and Cd-doped p-Si diodes have been investigated.•In Si, Cd is responsible for a change in diode exponetinal to Ohmic I–V behaviour.•Cd causes a material conductivity-type inversion fon p to n-type Si.•Cd doping is responsible for an increase in material resistivity.•Properties of Cd-doped p-Si diode are similar to those of devices that were found to be resistant to radiation damage. This study reports on a change in current-voltage (I–V) and capacitance-voltage (C–V) characteristics of silicon (Si) diodes due to doping Si with cadmium (Cd). Effects of Cd-doping on diode parameters and conduction mechanism are investigated. The results obtained here indicate that the diodes are well fabricated and introducing Cd in Si results in a diode I–V behaviour changing from normal exponential to ohmic. An ohmic behaviour indicates that the diode conduction mechanism is dominated by defect levels at the centre of the Si energy gap. These defects are responsible for generation of minority carriers to recombine majority carriers resulting in an increase in material resistivity. A change in a direction of a C–V trend showing an inversion of a material conductivity-type confirms the generation of minority carriers after doping Si with Cd. A high resistivity material is important for radiation detection since a full space charge region width can be attained at a reasonable operating voltage. The ohmic behaviour and a conductivity-type inversion have been observed on diodes that are resistant to radiation damage. Cd is, therefore, a suitable dopant in defect-engineering studies to improve radiation hardness of Si for high energy physics experiments.