5.Silicon Carbide Technology

5-4 SiC Semiconductor Crystal Growth

5-4 SiC Semiconductor Crystal Growth As of this writing, much of the outstanding theoretical promise of SiC electronics highlighted in the previous section has largely gone unrealized. A brief historical examination quickly shows that serious shortcomings in SiC semiconductor material manufacturability and quality have greatly hindered the development of SiC semiconductor electronics. From [...]

5-4-1 Historical Lack of SiC Wafers

5-4-1 Historical Lack of SiC Wafers Reproducible wafers of reasonable consistency, size, quality, and availability are a prerequisite for commercial mass production of semiconductor electronics. Many semiconductor materials can be melted and reproducibly recrystallized into large single crystals with the aid of a seed crystal, such as in the Czochralski method employed in [...]

5-4-2 Growth of 3C-SiC on Large-Area (Silicon) Substrates

5-4-2 Growth of 3C-SiC on Large-Area (Silicon) Substrates Despite the absence of SiC substrates, the potential benefits of SiC hostile-environment electronics nevertheless drove modest research efforts aimed at obtaining SiC in a manufacturable wafer form.Toward this end, the heteroepitaxial growth of single-crystal SiC layers on top of large-area siliconsubstrates was [...]

5-4-3 Growth of Hexagonal Polytype SiC Wafers

5-4-3 Growth of Hexagonal Polytype SiC Wafers In the late 1970s, Tairov and Tzvetkov established the basic principles of a modified seeded sublimation growth process for growth of 6H-SiC. This process, also referred to as the modified Lely process,was a breakthrough for SiC in that it offered the first possibility [...]

5-4-4 SiC Epilayers

5-4-4 SiC Epilayers Most SiC electronic devices are not fabricated directly in sublimation-grown wafers, but are instead fabricated in much higher quality epitaxial SiC layers that are grown on top of the initial sublimationgrown wafer. Well-grown SiC epilayers have superior electrical properties and are more controllable and reproducible than bulk [...]

5-4-4-1 SiC Epitaxial Growth Processes

5-4-4-1 SiC Epitaxial Growth Processes An interesting variety of SiC epitaxial growth methodologies, ranging from liquid-phase epitaxy, molecular beam epitaxy, and chemical vapor deposition(CVD) have been investigated . The CVD growth technique is generally accepted as the most promising method for attaining epilayer reproducibility, quality, and throughputs required for mass [...]

5-4-4-2 SiC Epitaxial Growth Polytype Control

5-4-4-2 SiC Epitaxial Growth Polytype Control Homoepitaxial growth, whereby the polytype of the SiC epilayer matches the polytype of the SiC substrate, is accomplished by “step-controlled” epitaxy . Step-controlled epitaxy is based upon growing epilayers on an SiC wafer polished at an angle (called the “tilt-angle” or “off-axis angle”) of [...]

5-4-4-3 SiC Epilayer Doping

5-4-4-3 SiC Epilayer Doping In-situ doping during CVD epitaxial growth is primarily accomplished through the introduction of nitrogen (usually) for n-type and aluminum (usually trimethyl- or triethylaluminum) for p-type epilayers . Some alternative dopants such as phosphorus and boron have also been investigated for the n-and p-type epilayers, respectively . [...]

5-4-5 SiC Crystal Dislocation Defects

5-4-5 SiC Crystal Dislocation Defects Table 5.2 summarizes the major known dislocation defects found in present-day commercial 4H- and 6H-SiC wafers and epilayers . Since the active regions of devices reside in epilayers, the epilayer defect content is clearly of primary importance to SiC device performance. However, as evidenced by [...]

5-5 SiC Device Fundamentals

5-5 SiC Device Fundamentals To minimize the development and production costs of SiC electronics, it is important that SiC device fabrication takes advantage of existing silicon and GaAs wafer processing infrastructure as much as possible. As will be discussed in this section, most of the steps necessary to fabricate SiC [...]