Evaluation of Free Carrier Lifetime and Deep Levels of the Thick 4H-SiC Epilayers

Abstract

Correlations between the free carrier lifetime of thick, lightly-doped n-type 4H-SiC epilayers and some deep levels (the Z 1/2 center, the EH 6/7 center and the D 1 center) were investigated. Concentrations of the Z 1/2 center and the EH 6/7 center correlated with the measured carrier lifetime to some extent. We have also compared the free carrier lifetime measured by time-resolved photoluminescence (TRPL) measurement and microwave-detected photoconductive decay (µ-PCD) measurement. The carrier lifetime measured by both technique was in close agreement. The carrier lifetime measured by LTPL increased at an elevated temperature of 500 K.

Negative-Ucarbon vacancy in 4H-SiC: Assessment of charge correction schemes and identification of the negative carbon vacancy at the quasicubic site

“…37 Thus, the difference in the spin localization on the two nearest Si neighbors of V − C (h, C 1h ) and V − C (k, C 1h ) is also in line with the prediction from calculations. Compared with the calculations, the two Si 5,6 (k) and C 1,2 (k) hf structures, which were observed for V − C (k, C 1h ) but have not been detected for V − C (h, C 1h ), can also identified as due to the hf interaction of the electron spin with the nuclear spin of one 29 Si atom occupying one of two Si sites in the third neighbor and with one 13 C atom occupying two C sites in the second neighbor, respectively (see Table II). Such a good agreement in the spin-Hamiltonian parameters obtained by EPR and supercell calculations firmly supports the identification of the new EPR spectrum to be related to V − C (k).…”

“…The strong and weak inner hf lines have intensity ratios with the main line of ß10% and ß2.5%, respectively [Figs. 6(e) and 6(f)], and are assigned to be the hf structures due to the hf interaction between the electron spin and the nuclear spin of one 29 Si atom occupying one of two Si sites, labeled as Si 5,6 (k), and of one 13 C atom (I = 1/2 and a natural abundance of ß1.1%) at two C sites, labeled as C 1,2 (k), respectively. The neighbor sites of Si 5,6 (k) and C 1,2 (k) will be described later with the help of first principles simulations.…”

“…37 We label these C 1h configurations of V − C at low temperatures as V − C (k, C 1h ) and V − C (h, C 1h ). The Si 5,6 (k), C 1,2 (k), and Si 3,4 (k) hf lines each split into six lines corresponding to six possible defect orientations (with respect to the direction of magnetic field), indicating their lowest symmetry C 1 in a hexagonal lattice. Analyzing the obtained angular dependences using the spin-Hamiltonian Eq (1), we obtain the g-tensor for V − C (k, C 1h ) and the hf A-tensors for Si 5,6 (k), C 1,2 (k), and Si 3,4 (k).…”

“…It was suggested by different studies [4][5][6][7][8] that the carrier lifetime in bulk 4H -SiC is limited by the Z 1 /Z 2 deep level located at ß0.65 eV below the conduction band minimum (CBM) (ßE C − 0.65 eV). 9,10 Since the Z 1 /Z 2 defect is always present in as-grown material 10 and has strong influence on device applications of SiC, there has been considerable effort in identification and elimination of the defect.…”

Development of Process Technologies for High-Performance MOS-Based SiC Power Switching Devices

“…Although studies on growth and characterization of 4H-SiC epilayers has been carried out intensively, systematic studies on carrier lifetime in SiC epilayers are limited in literature [74][75][76][77][78]. Deep levels in the bandgap are believed to severely limit the carrier lifetime of SiC epilayers by acting as recombination centers.…”