A method to observe field-region oxide charge and inter-electrode isolation from $CV$-characteristics of $n$-on-$p$ devices

• DOI: 10.48550/arxiv.2402.04365
• Publication Date: 2024-02-06
• Authors: T. Abdilov; N. Akchurin; Christopher P. Carty; Y. Kazhykarim; V. Kuryatkov; T. Peltola; A. R. Wade
• Keywords: Isolation

$N$-on-$p$ silicon sensors will be utilized in the Compact Muon Solenoid (CMS) detector's tracker and High Granularity Calorimeter (HGCAL) Luminosity upgrade of Large Hadron Collider (HL-LHC). Among their several advantages terms radiation hardness over traditional $p$-on-$n$ extreme environment HL-LHC are electron collection instead holes overlapping maxima weighting electric fields at charge-collecting electrodes. The disadvantage multi-channel SiO$_2$-passivated $n$-on-$p$ is generation an inversion layer under Si/SiO$_2$-interface by a positive interface-oxide-charge ($N_\textrm{ox}$) that high densities can compromise position resolution creating conduction channel between This issue typically addressed including additional isolation implants ($p$-stop, $p$-spray) $n^+$-electrodes. Focusing on guard-ring regions where no applied electrodes, capacitance-voltage ($CV$) characterization study both 6-inch wafer test diodes 8-inch HGCAL prototype pre-series showed distinct threshold voltage ($V_\textrm{th,iso}$) $CV$-characteristics biased $n^+$-electrode when its enclosing was left floating. When reproduced simulations, measured $V_\textrm{th,iso}$ found to contain information field-region $N_\textrm{ox}$ indicate two electrodes become electrically isolated influence reverse bias voltage. Together with previous studies inter-electrode irradiated sensors, results sensitive without may feasible future HEP experiments.