Investigation of high resistivity p-type FZ silicon diodes after 60Co {\gamma}-irradiation

• Main Authors: Liao, Chuan, Fretwurst, Eckhart, Garutti, Erika, Schwandt, Joern, Pintilie, Ioana, Himmerlich, Anja, Moll, Michael, Gurimskaya, Yana, Li, Zheng
• Format: Journal Article
• Language: English
• Published: 27-06-2023
• Subjects: Physics - Instrumentation and Detectors
• DOI: 10.48550/arxiv.2306.15336

In this work, the effects of $^\text{60}$Co $\gamma$-ray irradiation on high
resistivity $p$-type diodes have been investigated. The diodes were exposed to
dose values of 0.1, 0.2, 1, and \SI{2}{\mega Gy}. Both macroscopic ($I$--$V$,
$C$--$V$) and microscopic (Thermally Stimulated Current~(TSC)) measurements
were conducted to characterize the radiation-induced changes. The investigated
diodes were manufactured on high resistivity $p$-type Float Zone (FZ) silicon
and were further classified into two types based on the isolation technique
between the pad and guard ring: $p$-stop and $p$-spray. After irradiation, the
macroscopic results of current-voltage and capacitance-voltage measurements
were obtained and compared with existing literature data. Additionally, the
microscopic measurements focused on the development of the concentration of
different radiation-induced defects, including the boron interstitial and
oxygen interstitial (B$_\text{i}$O$_\text{i}$) complex, the carbon interstitial
and oxygen interstitial C$_\text{i}$O$_\text{i}$ defect, the H40K, and the
so-called I$_\text{P}^*$. To investigate the thermal stability of induced
defects in the bulk, isochronal annealing studies were performed in the
temperature range of \SI{80}{\celsius} to \SI{300}{\celsius}. These annealing
processes were carried out on diodes irradiated with doses of 1 and
\SI{2}{\mega Gy} and the corresponding TSC spectra were analysed. Furthermore,
in order to investigate the unexpected results observed in the $C$-$V$
measurements after irradiation with high dose values, the surface conductance
between the pad and guard ring was measured as a function of both dose and
annealing temperature.