TCAD simulation for alpha-particle spectroscopy using SIC Schottky diode

Abstract

There is a growing requirement of alpha spectroscopy in the fields context of environmental radioactive contamination, nuclear waste management, site decommissioning and decontamination. Although silicon-based alpha-particle detection technology is mature, high leakage current, low displacement threshold and radiation hardness limits the operation of the detector in harsh environments. Silicon carbide (SiC) is considered to be excellent material for radiation detection application due to its high band gap, high displacement threshold and high thermal conductivity. In this report, an alpha-particle-induced electron-hole pair generation model for a reverse-biased n-type SiC Schottky diode has been proposed and verified using technology computer aided design (TCAD) simulations. First, the forward-biased I-V characteristics were studied to determine the diode ideality factor and compared with published experimental data. The ideality factor was found to be in the range of 1.4-1.7 for a corresponding temperature range of 300-500 K. Next, the energy-dependent, alpha-particle-induced EHP generation model parameters were optimised using transport of ions in matter (TRIM) simulation. Finally, the transient pulses generated due to alpha-particle bombardment were analysed for (1) different diode temperatures (300-500 K), (2) different incident alpha-particle energies (1-5 MeV), (3) different reverse bias voltages of the 4H-SiC-based Schottky diode (-50 to -250 V) and (4) different angles of incidence of the alpha particle (0°-70°).The above model can be extended to other (wide band-gap semiconductor) device technologies useful for radiation-sensing application.

Transient behaviour analysis in silicon carbide alpha particle detector using TCAD and SRIM simulation

“…In order to analyze the time-resolved characteristics of the 4H-SiC SBD for alpha particles with different energies, the ionization results of the SRIM should be introduced into the TCAD model. Meanwhile, the transient single-event current analysis of TCAD model needs to build and set its linear charge deposition (LCD) value with unit of pC/μm [28] for ionization charges calculation. To accomplish these ionization results as input of the TCAD, we need to calculate the energy deposited per micrometer by using the ionization distribution and then determine the number of electron-hole pairs generated per micrometer.…”

Time Resolution of the 4H-SiC PIN Detector

“…The drift velocity v(r) is given by μ SiC • E(r), where μ SiC is the mobility in SiC. The mobility model of SiC in RASER is based on [29], and the sum of the currents induced by all electrons and holes is the total current. In the simulation, the influence of nonuniform charge deposition and impact position on the time resolution is simulated by GEANT4.…”

Timing Performance Simulation for 3D 4H-SiC Detector

“…where − → r is the drifting charge trajectory of electron or hole; q is the charge, − → v ( − → r ) is the drift velocity; and − → E w ( − → r ) is the weighting potential. − → v ( − → r ) is calculated by µ SiC • E( − → r ), and the mobility distribution of electron and hole in 4H-SiC with electric field is shown in Figure 4a, where the mobility model refers to [29]. The velocity of the electron was ∼1.6 × 10 7 cm•s −1 , and the hole was ∼9.5 × 10 6 cm•s −1 when the electric field in the detector was around 10 V/µm as shown in Figure 4b.…”