Excess carrier recombination lifetime of bulk n-type 3C-SiC

Abstract

Transient absorption technique was used to determine carrier lifetimes in 3C-SiC grown on Si and 6H-SiC substrates. A slow lifetime component originated from minority carrier traps and pointed out to the trap saturation with increasing injection. Recombination lifetime in different samples varied between 0.5–120 ns. Its value decreased with excess carrier density in the transition range between minority-carrier-lifetime and high-injection lifetime but abnormally increased above the carrier density of 2×1017 cm−3. Negligible contribution of surface and Auger recombination to recombination lifetime peculiarities was observed. Possible mechanisms of the observed lifetime variation are discussed.

Considerably long carrier lifetimes in high-quality 3C-SiC(111)

“…3(b), the fitted s ef f values decrease from 8.2 to 7.3 ls with increasing the injection level, indicating that the surface recombination still gives a contribution at this time range but smaller than the impact in the initial stage. This measured carrier lifetime in as-grown 3C-SiC is much higher than the reported values in 3C-SiC grown by other methods, [19][20][21] even a little bit higher than the typical values in as-grown 4H-SiC. [11][12][13][14][15] The maximum carrier lifetime reported in asgrown 4H-SiC is 8.6 ls, 11 which was measured by l-PCD in a high-quality 50 lm thick CVD epilayer under an injection of 5 Â 10 12 cm À2 .…”

“…[5][6][7] After the progress of different growth techniques in the last decade, free standing or thick (>100 lm) 3C-SiC has been demonstrated. 4 In these thick layers grown using either undulant Si, 19,20 or 4H-SiC, 19 or 6H-SiC as substrates, 20,21 however, the carrier lifetime is rather short. It is ranging from a few to 120 ns.…”

“…[18][19][20][21] In early 3C-SiC epitaxial layers with the thicknesses of 4-9 lm grown on silicon substrates, the excess carrier decay curves exhibited fast (a few ls) and slow (>1 ms) components, which was suggested to be due to electron trapping at deep defect levels. 18 It is not unexpected since the residual large strain results in a serious deterioration of the crystallinity and a defect-rich interface in such thin layers.…”

Terahertz conductivity and ultrafast dynamics of photoinduced charge carriers in intrinsic 3C and 6H silicon carbide

“…22 Both observations are consistent with previous studies covering millisecond time windows with nanosecond time resolution. 10,11 The relaxation and recombination mechanism of photogenerated carriers in 3C-SiC is not yet well understood and requires further studies, beyond the scope of the present work. On the contrary, in the case of 6H-SiC, we find a much faster decay of the photoinduced charge carriers.…”

“…The optical generation of charge carriers circumvents complications arising from chemical doping and, in addition, provides the opportunity to measure out-of-equilibrium parameters. a) Electronic mail: rubano@fisica.unina.it So far, the dynamics of photoinduced charge carriers in intrinsic 3C-and 6H-SiC has been studied using pumpprobe experiments [8][9][10] , however, with a time resolution of nanoseconds and at optical probe frequencies, far above the charge-carrier scattering rates that usually lye in the terahertz (THz) frequency range. 12 Deeper insight could be obtained by performing conductivity measurements using THz electromagnetic pulses having picosecond duration.…”