Nondestructive microstructural investigation of defects in 4H-SiC epilayers using a multiscale luminescence analysis approach

Abstract

The development of metal oxide semiconductor field effect transistors (MOSFETs) utilizing epitaxially grown 4H-SiC has accelerated in recent years due to their favorable properties, including a high breakdown field, high saturated electron drift velocity, and good thermal conductivity. However, extended defects in epitaxial 4H-SiC can affect both device yields and operational lifetime. In this work, we demonstrate the importance of a multiscale luminescence characterization approach to studying nondestructively extended defects in epitaxial 4H-SiC semiconducting materials. Multiscale luminescence analysis reveals different aspects of excess charge carrier recombination behavior based on the scale of a particular measurement. Combining measurements of the same extended defect area at different scales tells us more about the essential nature of that defect and its microstructure. Here, we use photoluminescence imaging and cathodoluminescence spectrum imaging to investigate the recombination behavior of several different types of extended defects, including stacking faults, inclusions, and basal plane dislocations. A detailed understanding of the optoelectronic properties of extended defects in epitaxial SiC helps elucidate the microstructure of extended defects and can provide pathways to mitigate detrimental changes during device operation related to their evolution, such as the recombination enhanced dislocation glide effect that affects SiC-based MOSFETs.

4H-SiC MOSFET Threshold Voltage Instability Evaluated via Pulsed High-Temperature Reverse Bias and Negative Gate Bias Stresses

“…The gate insulation layer is a 50 nm thick deposited oxide layer through a Low-Pressure Chemical Vapor Deposition (LPCVD) process followed by a state-of-the-art NO-based post-oxide deposition annealing [22]. The semiconductor materials were characterized at the beginning of the device fabrication process using microscopic techniques in order to select those devices without any visible epitaxial defect that may affect the device's reliability [12,23]. Firstly, the optical inspection at the surface of the epitaxial layer is carried out with Candela 8520 using a KLA-Tencor equipment scan which allows us to detect surface defects such as droplets, carrots, triangles, micro-pits, etc.…”

Influence of Growth Process on Suppression of Surface Morphological Defects in 4H-SiC Homoepitaxial Layers

“…The main destructive defects are instant surface dislocation (BPD) defects and stacking faults (SF), which are likely to continuously increase the on-resistance of bipolar devices [25][26][27][28][29][30][31][32][33][34][35]. Surface defects, such as dump, scratch, particle, downfall (DF), triangle (TD), comet and carrot defects, are typically detrimental and easily observable, and often lead to device failure [36][37][38][39][40][41][42]. Therefore, one of the main challenges in 4H-SiC epitaxial growth is to decrease the defect density of the epitaxial layer.…”

“…The main destructive defects are instant surface dislocation (BPD) defects and stacking faults (SF), which are likely to continuously increase the on-resistance of bipolar devices [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Surface defects, such as dump, scratch, particle, downfall (DF), triangle (TD), comet and carrot defects, are typically detrimental and easily observable, and often lead to device failure [ 36 , 37 , 38 , 39 , 40 , 41 , 42 ].…”

Co-wide-bandgap conformally heteroepitaxial perovskite–monolithic SiC nanowire array with quantum-confined blue luminescence

“…This photon energy is much smaller than the bandgap of bulk 6H-SiC (2.86 eV at T = 300 K), 27) hence this PL originates from some surface defects 9) or extended defects such as stacking faults and dislocations. 11,[28][29][30] The unetched region exhibited no PL [Fig. 1(d)].…”