Electrical Characteristics and Fast Neutron Response of Semi-Insulating Bulk Silicon Carbide

Abstract

Abstract-The electrical characteristics and fast neutron response of a High Temperature Chemical Vapour Deposition (HTCVD) grown semi-insulating bulk SiC wafer has been measured. Current -Voltage measurements demonstrated a low leakage current in the region of 10 -10 to 10 -12 A with a bulk resistivity of at least 10 12 -10 13 Ω.cm. Alpha particle spectroscopy measurements demonstrated an electron charge collection efficiency of up to 90% with reasonable reproducibility of the acquired spectra. Evidence of (incident particle) rate dependent polarisation was seen following a constant applied bias combined with alpha irradiation over a period of time (order of tens of minutes). The ability of the wafer to detect fast neutrons was demonstrated and a comparison drawn with the MCNPX simulated response of a bulk SiC device. Comparing the MCNPX simulated response of a bulk SiC device to that of a silicon device suggests a superior ability to detect fast neutrons with an intrinsic efficiency 1.7 times that of silicon.

SiC Detectors for Sub-GeV Dark Matter

“…The best measure of the drift constant µτ scat in 4H-SiC (the only polytype for which detailed studies are available) was found to be µτ scat ∼ 3 × 10 −4 cm 2 /V, and for a saturation drift field of 8 kV/cm, we find a maximum drift length D ∼ 2.4 cm [65]. While this does imply full charge collection for devices up to 1 cm thick, the very high voltages required are likely to induce some measure of charge breakdown, despite the very high dielectric strength of SiC.…”

“…The only studies to demonstrate near full charge collection in SiC are Refs. [21,32,65], which all study energy deposition in thin films (∼40 µm). Studies of depositions in a ten times larger detector volume in e.g.…”

“…This gives the drift length D = v d τ scat → v d,sat τ scat in the high-field limit [21], where τ scat is the carrier scattering lifetime. Given this drift length, we can model the CCE as [65] CCE…”

“…The devices studied in Refs. [21,32,65] are all thin films which did not break down at field strengths in this regime; however, for low temperature operation of these devices, voltages of this magnitude are atypical for monolithic, gram-scale detectors. Ref.…”

Structural Controlling of Highly-Oriented Polycrystal 3C-SiC Bulks via Halide CVD

“…The cubic polytype of SiC (3C-SiC) can be used as a structural material, particularly in harsh environments, due to its high hardness and strength, and good thermal shock resistance and corrosion resistance [1,2,3]. Generally, SiC bulks are densified using method such as pressureless sintering, spark plasma sintering, and liquid-phase sintering with additives (Al 2 O 3 , AlN, B, C, and B 4 C) [4,5,6,7,8].…”