Discovered in 1891, Silicon carbide (SiC) is known for its extreme hardness and High-temperature resistance, and is used majorly since then as an abrasive, in cutting tools, bearings and in high temperature applications like crucibles for melting metals etc. Recently, demand of single crystal SiC wafers is gaining momentum in electronic chip manufacturing in semiconductor industries. Single crystal SiC is an electrical insulator and is optically transparent in pure form. Dopant like Nitrogen or Aluminum are added to tailor its electronic properties making it semiconducting. Addition of dopant also changes the color from transparent to green or blue transparent depending on the level of dopant impurities added. Also electrical conductivity can be controlled by varying doping concentration. SiC wafers have certain properties far superior than its counterpart Silicon wafer, making it strong contender for replacing Silicon wafer from semiconductor industry. Recently, Tesla has been using SiC based semiconducting chips in its electric vehicles. So in this article we will discuss what are the properties of SiC wafer which makes them better option for electronic chip manufacturing.
SiC has a wide band gap of 3.26 eV compered to Si which is 1.12 eV. In semiconductor chip manufacturing industry wide band gap offers an advantage. During the operation, temperature of device rises and with rise in temperature band gap shrinks. At high temperature Si based devices losses their efficiency or may breakdown due to their lower band gap while SiC based devices will work without any problem due to their sufficiently large band gap. SiC based devices can operate upto 400 degree C without breakdown. So this eliminates the need of extra cooling accessories like fan or heat sink thus reducing overall size and power consumption of the device.
Again due to the wide band gap of SiC, power loss in form of heat is less due to lower leakage currents. For Silicon based devices to achieve such lower leakage current and power loss the size of the device must be significantly increased. SiC based devices with same functionality or capabilities as Si based devices are almost 10 times smaller . Also SiC based devices of size and functionality similar to Si based device can handle 10 times more voltage.
In order to cut down the increase in ON resistance at high voltage in Si based devices, minority carrier Si based devices like IGBT are used. But this results in an increased switching loss in the form of heat and thus these devices cannot be operated at high frequencies. On the other hand majority carrier SiC based devices like MOSFET or Schottky diodes can be operated at higher voltages without increase in ON resistance. Thus, being a majority carrier devices, they can be operated at higher frequency range with minimum heat loss.
SiC carbide is resistant to thermal shocks and is stable up to the temperature of 2000 degree C. As already discussed SiC based devices can operate up to 400 Degree C without loss of efficiency.
Unlike Si, SiC is chemically inert material with resistance to corrosion through any kind of acid/bases or through oxidation. It only reacts with chlorine but only at 900 Degree C. So electronic devices made from SiC can operate not only in high temperature conditions but also in harsh chemical environment. Due to these properties SiC is also quite promising candidate for manufacturing high power semiconducting devices for space exploration projects.
Looking at the advantages of Silicon Carbide over Silicon and looking at the current market and research trend, semiconductor device manufacturing industries are now shifting their focus on SiC. We also put our best effort on delivering trending materials and technology to our customers, therefore we have included Silicon Carbide wafer in Vritra Technologies product portfolio. Please feel free to contact us for any requirement related to SiC wafer.