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Manufacturing of SiC (Silicon Carbide) Circuits

Silicon carbide is a wide-bandgap semiconductor material with special properties that allows operation at high temperatures and is particularly well suited for power semiconductors. Fast and efficient switching of high voltages and currents, high breakdown voltages, resistance to radiation effects, and good thermal conductivity are the positive properties of silicon carbide. Disadvantages are the high cost and the high temperatures required for processing.

Particularly critical are the thermal processes for the electrical activation of implanted dopants Al, B (p-doping), N or P (n-doping). Furnaces for silicon carbide processing must be able to reach up to 2000 °C, whereas manufacturing circuits from silicon or GaAs normally requires temperatures up to 1200 °C. There are also vertical furnaces that can reach these temperatures using MoSi₂ heaters or graphite heaters.

Thermal Processes in SiC Technology

For the manufacture of SiC electronics, various thermal process steps are required, similar to the production of silicon circuits. The following table provides an overview of the individual process steps, the furnace types used, and the temperatures applied.

Process	Description	Furnace type	Temperature
Activation	Activation of dopants after ion implantation	High-temperature furnace	2000 °C
Oxynitridation	Deposition of oxynitride	High-temperature LPCVD furnace	1400 °C
TEOS Deposition	Deposition of LPCVD oxide from TEOS (tetraethoxysilane)	High-temperature LPCVD furnace	1350 °C
Thermal oxidation	Thermal oxidation with dry or wet oxygen	Vertical furnace	1200 °C
PDA Anneal	PDA (post-deposition anneal) of deposited metal layers	RTP system	1100 °C
Contact anneal	Short-term annealing of contacts	RTP system	1000 °C

Heating Elements

JTEKT (formerly Koyo Thermo Systems) develops and manufactures its own, patented heating elements with special properties. Ordered by increasing temperature, JTEKT can offer the following heating elements:

LGO Heating Element
(light gauge overbend)

120 °C – 1150 °C

HGC Heating Element
(high gauge coil)

400 °C – 1250 °C

MoSi2 Heating Element
(Molybdenum disilicide)

up to 1400 °C

Carbon Heating Element

up to 2000 °C

Equipment Images

Both small, manually loaded systems for research and development and fully automated machines for mass production that operate cassette-to-cassette can be offered. Below we show some images of production systems.