Different from S1C discrete devices which pursue high voltage, high power, high frequency and high temperature characteristics, the research goal of SiC integrated circuit is mainly to obtain high temperature digital circuit for intelligent power ICs control circuit. As SiC integrated circuit for internal electric field is very low, so the influence of the microtubules defect will greatly abate, this is the first piece of monolithic SiC integrated operational amplifier chip was verified, the actual finished product and determined by the yield is much higher than microtubules defects, therefore, based on SiC yield model and Si and CaAs material is obviously different. The chip is based on depletion NMOSFET technology. The main reason is that the effective carrier mobility of reverse channel SiC MOSFETs is too low. In order to improve the surface mobility of Sic, it is necessary to improve and optimize the thermal oxidation process of Sic.
Purdue University has done a lot of work on SiC integrated circuits. In 1992, the factory was successfully developed based on reverse channel 6H-SIC NMOSFETs monolithic digital integrated circuit. The chip contains and not gate, or not gate, on or gate, binary counter, and half adder circuits and can operate properly in the temperature range of 25°C to 300°C. In 1995, the first SiC plane MESFET Ics was fabricated using vanadium injection isolation technology. By precisely controlling the amount of vanadium injected, an insulating SiC can be obtained.
In digital logic circuits, CMOS circuits are more attractive than NMOS circuits. In September 1996, the first 6H-SIC CMOS digital integrated circuit was manufactured. The device uses injected N-order and deposition oxide layer, but due to other process problems, the chip PMOSFETs threshold voltage is too high. In March 1997 when manufacturing the second generation SiC CMOS circuit. The technology of injecting P trap and thermal growth oxide layer is adopted. The threshold voltage of PMOSEFTs obtained by process improvement is about -4.5V. All the circuits on the chip work well at room temperature up to 300°C and are powered by a single power supply, which can be anywhere from 5 to 15V.
With the improvement of substrate wafer quality, more functional and higher yield integrated circuits will be made. However, when the SiC material and process problems are basically solved, the reliability of device and package will become the main factor affecting the performance of high-temperature SiC integrated circuits.
Post time: Aug-23-2022