Growth of Czochralski Silicon Crystals with Ultralow Carbon Concentrations for High-Power Insulated-Gate Bipolar Transistor Devices

摘要

The effects of the argon gas flow in a Czochralski (CZ) silicon growth furnace and the evaporation of carbon monoxide (CO) from the silicon melt on the carbon concentration in 8-inch CZ silicon crystals were studied by evaluating the carbon concentrations in the crystals using photoluminescence spectroscopy. Preventing silicon monoxide from flowing through the side of the heater and the graphite susceptor and preventing back-diffusion of CO from the top of the graphite susceptor effectively reduced carbon contamination during CZ silicon growth. In addition, CO was evaporated from the melt by increasing the gas flow rate above the melt surface. Owing to the effects of CO evaporation from the melt, 8-inch CZ silicon crystals were grown with a carbon concentration considerably lower than that in floating-zone silicon.