Improving 5V Digital 4H-SiC CMOS ICs for Operating at 400°C Using PMOS Channel Implantation

Abstract

In this work, the impact of a shallow aluminum channel implantation on the channel properties of SiC p-MOSFETs and digital SiC CMOS devices is investigated. For this purpose, p-MOSFETs, CMOS inverters and ring oscillators with different channel implantation doses were fabricated and electrically characterized. The threshold voltage of the resulting p-MOSFETs was shifted from-5 V to-3.6 V whereas the effective channel mobility was slightly decreased from 11.8 cm2/Vs to 10.2 cm2/Vs for a p-MOSFET channel implantation dose of 2∙1013 cm-2 compared to the non-implanted channel. The resulting p-MOSFETs enable SiC CMOS logic circuits to operate with a 5 V power supply and to satisfy 5 V TTL input level specification over the whole temperature range of 25°C to 400°C. Furthermore the propagation delay time of inverters was reduced by 80% at 25°C and 40% at 400°C compared to inverters without p-MOSFET channel implantation.

Integrated Digital and Analog Circuit Blocks in a Scalable Silicon Carbide CMOS Technology

“…More recently, a promising new SiC CMOS technology candidate arose. This state-of-the-art 4H-SiC CMOS [41], [42] was developed by the Fraunhofer Institute for Integrated Systems and Devices Technology (IISB), based in Erlangen, Germany. The group of Mantooth at the University of Arkansas reported high-temperature memory SRAM cells [43] in this technology and Fraunhofer IISB demonstrated compatible UV photodetectors [44], [45] and temperature sensors [46].…”

Visible Blind Quadrant Sun Position Sensor in a Silicon Carbide Technology

“…The photodetectors are implemented in the novel open silicon carbide CMOS technology [9][10][11] developed by Fraunhofer IISB in Germany. The fabrication process front-end-of-line (FEOL) is implemented by ion implantation, which is used for the photodetector realization.…”

“…Unfortunately, the HiTSiC technology was discontinued in 2018, which left the need for a new and open SiC CMOS technology. This need is addressed by the recent development of the SiC CMOS at Fraunhofer IISB [9][10][11]. This work reports on a quadrant sun position sensor in 4H-SiC (Figure 1), which builds on the previously reported integrated 3D optics approach [12] to aim for miniaturization of the device in the future.…”

Integrated 64 pixel UV image sensor and readout in a silicon carbide CMOS technology

“…The implementation of integrated low-voltage circuitry in silicon carbide has been feasible for over a decade, although the accessibility to the technologies has remained limited. The most promising technologies under development today are a BJT technology 21 , 22 for high temperature and harsh environments, called HOTSiC, at the KTH in Sweden and a 4H-SiC CMOS 23 – 25 at the Fraunhofer Institute for Integrated Systems and Devices Technology (IISB), based in Erlangen, Germany. The latter has full capability for designs with complementary devices, while the BJT technology is NPN only with pull-up resistors.…”