CVD growth and properties of on-axis vanadium doped semi-insulating 4H-SiC epilayers

Abstract

Highly resistive homoepitaxial layers of 4H-SiC have been grown on the Si-face of nominally on-axis, n-type substrates using chemical vapor deposition (CVD). Vanadium tetrachloride has been used as V-dopant which is responsible for the high resistivity of the epilayers. 100% 4H-polytype was reproduced in the epilayers using optimized on-axis growth process and the upper limit of Vanadium tetrachloride flow rate for achieving defect-free high resistivity homoepitaxial layers was established. A resistivity of more than 1x10 5 Ω-cm has been achieved in epilayers with a very low concentration of V (1x10 15 cm-3). Owing to the low concentration of V, superior epilayer structural quality was achieved compared to V-doped and standard high purity semi-insulating bulk grown material of similar resistivity. Epitaxial layers with varying Vanadium tetrachloride flow have also been grown to study the influence of V concentration on the polytype stability, structural quality and optical and electrical properties of epilayers. A clear correspondence has been observed in the flow-rates of Vanadium tetrachloride, the atomic concentration of V and electrical, optical and structural properties of epilayers.

Optical Properties of Vanadium in 4 H Silicon Carbide for Quantum Technology

“…We examined a single-crystal 4H SiC sample with an homoepitaxial layer grown on an on-axis substrate [20]. The epilayer is 25 µm thick and was grown with vanadium tetrachloride as a source of V-dopant, leading to an inclusion density of 2 × 10 16 V/cm 3 as measured by SIMS.…”

Controlling the electrical resistivity of porous silicon carbide ceramics and their applications: A review

“…These dopants can act as donors (n‐type, electrons as the charge carriers, e.g., P, N 2 ), acceptors (p‐type, holes as the charge carriers, e.g., Al, B, Ga, Sc), or charge arrestors (e.g., V and Be) depending on the electronic configuration of each element. The presence of donors or acceptors decreases the electrical resistivity by providing charge carriers, while charge arrestors create deep levels within the bandgap and tend to increase the electrical resistivity by capturing the charge carriers 133,140 …”

“…Kultayeva et al 27 reported a difference of four orders of magnitude in the electrical resistivity of N 2 -doped (2.1 × 10 -1 Ω.cm) and undoped (1.2 × 10 3 Ω⋅cm) SiC at the same porosity of 62%. In addition to N 2 , 122-126 O 2 , 126,127 Al, [128][129][130][131] B, 131,132 V, 133,134 Be, 131 Ga, 122 Sc, 135,136 P, 123,124,137 C, 127 etc. are soluble in the SiC lattice.…”

“…The presence of donors or acceptors decreases the electrical resistivity by providing charge carriers, while charge arrestors create deep levels within the bandgap and tend to increase the electrical resistivity by capturing the charge carriers. 133,140 Kultayeva et al 27 studied the effects of various dopants (N, B, Al, Sc, and V) on the electrical resistivity of SiC at a fixed additive content (1 vol.%) and porosity (∼62%). The highest electrical resistivity was reported for V-doped SiC (4.2 × 10 2 Ω⋅cm) mainly because of the creation of deep levels in its bandgap.…”

Bright single photon sources in lateral silicon carbide light emitting diodes

“…The p-i-n diodes were fabricated on a vertical stack of epilayers that was grown by CVD with the following structure: n + 4H-SiC substrate/semi-insulating (SI) layer (10 µm thick)/n − (17 µm thick). SI layer was grown through in-situ vanadium doping during growth using vanadium tetrachloride (VTC) in bubbler configuration 22 A high concentration of vanadium is known to produce extended defects in the epilayer. The flow rate of VTC was optimized to achieve defect free epilayer with SI properties (resistivity >10 5 cm).…”