Compensating defect centres in semi-insulating 6H-SiC

Abstract

Photoinduced transient spectroscopy (PITS) has been applied to study electronic properties of point defects associated with charge compensation in semi-insulating (SI) 6H-SiC substrates. The photocurrent relaxation waveforms were digitally recorded in a wide temperature range of 20–800 K and in order to extract the parameters of defect centres, a two-dimensional analysis of the waveforms as a function of time and temperature has been implemented. As a result, the processes of thermal emission of charge carriers from defect centres were seen on the spectral surface as the folds, whose ridgelines depicted the temperature dependences of emission rate for detected defect centres. The new approach was used to compare the defect levels in vanadium-doped and vanadium-free (undoped) SI 6H-SiC wafers.

High Purity Semi-Insulating 4H-SiC Epitaxial Layers by Defect-Competition Epitaxy: Controlling Si Vacancies

“…The experimental details and photocurrent relaxation analysis are found elsewhere. 18) HRPITS in low doped n-type (C/Si: 0.9) samples revealed 19) [Fig. 2(b)] the presence of EH 6=7 (V C related traps), as expected 13) under Si-rich growth conditions.…”

“…High resolution X-ray diffraction rocking curve of a 60 µm thick epilayer grown on a 4H-SiC, 8 0 off towards(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) substrate (a)Schematic band diagram for n-type (C/Si: 0.9) (b) Deep defect levels located using HRPITS (a) Schematic band diagram for HPSI (C/Si: 1.4) (b) Deep defect levels located using HRPITSFigure 1…”

“…The resulting photocurrent transients are recorded as a function of temperature (77-750K), revealing information about traps in the material. The experimental details and photocurrent relaxation analysis are found elsewhere 18 . HRPITS in low doped n-type (C/Si: 0.9) samples revealed 19 [Figure 3(b)] the presence of EH 6/7 , (V C related traps), as expected 13 under Si-rich growth conditions.…”

Characterization of carrier behavior in photonically excited 6H silicon carbide exhibiting fast, high voltage, bulk transconductance properties

“…We exploit V doped semi-insulating (SI) SiC as it has been studied extensively as the base substrate for LED and device production. But the physics of the semi-insulating conduction process are unexplored and not fully understood due to the complexity of the defect structure 19 . As is well documented in the literature, V at the substitutional Si site forms deep mid-gap levels in most polytypes of SiC with amphoteric behavior (i.e., exhibit acceptor and donor states depending on the Fermi level 20 ).…”