Development of 4H–SiC Epitaxial Growth Technique Achieving High Growth Rate and Large-Area Uniformity

Abstract

A vertical hot-wall epi-reactor that makes it possible to simultaneously achieve a high growth rate and large-area uniformity has been developed. A maximum growth rate of 250 µm/h is achieved with a mirror-like morphology at 1650 °C. Under a modified epi-reactor setup, a thickness uniformity of 1.1% and a doping uniformity of 6.7% for a 65-mm-radius area are achieved while maintaining a high growth rate of 79 µm/h. A low doping concentration of ∼1×1013 cm-3 is obtained for a 50-mm-radius area. The low-temperature photoluminescence (LTPL) spectrum shows the predominance of free exciton peaks with only few impurity-related peaks and the L1 peak below detection limit. The deep level transient spectroscopy (DLTS) measurement for an epilayer grown at 80 µm/h shows low trap concentrations of Z1/2: 1.2×1012 and EH6/7: 6.3×1011 cm-3. A 280-µm-thick epilayer with a RMS roughness of 0.2 nm and a carrier lifetime of ∼1 µs is obtained.

Formation of extended defects in 4H‐SiC epitaxial growth and development of a fast growth technique

“…Prevention of homogeneous gas-phase nucleation of clusters is commonly recognized as a crucial issue in SiC CVD epitaxy to increase the growth rate. The effectiveness of lowering the system pressure has been demonstrated in suppressing gas-phase nucleation and obtaining a high growth rate with a conventional H 2 + SiH 4 + C 3 H 8 gas system [18,19]. The addition of HCl to the conventional gas system or the use of a chlorine-containing precursor has also been reported to achieve suppression of silicon cluster formation and high growth rates [20][21][22][23].…”

Observations of Overlapped Single Shockley Stacking Faults in 4H-SiC PiN Diode

“…• o-cut n + 4H-SiC substrate by epitaxial growth in a vertical hot-wall reactor [3]. The substrates used in this work were n-type (0001) 4H-SiC wafers tilted at 8…”

Precursors and defect control for halogenated CVD of thick SiC epitaxial layers

“…The formation of silicon droplets can be avoided by lowering the growth pressure and/or increasing the carrier gas flow (H2) to minimize the homogeneous gas phase nucleation [40][41][42] or by increasing the growth temperature to evaporate the silicon droplets [43]. Low pressure vertical hot wall CVD (15-20 Torr) using standard chemistry (SiH4 + C3H8) has been reported to achieve high growth rates (> 100 µm/h) [44,45]. On the other hand introducing chlorine into the gas mixture (chloride-based) [46], by adding HCl [47][48][49][50] or using some chlorinated silicon precursor, such as trichlorosilane (TCS) [51][52][53] or tetrachlorosilane (TET) [54][55][56], or by using methyltrichlorosilane (MTS) [57][58][59][60] as a single molecule will prevent nucleation in the gas phase, due to the stronger Si-Cl bond (400 kJ/mol) as compared to the Si-Si bond (226 kJ/mol) [61].…”