GlobalWafers Japan Co. | Date: 2015-05-22
According to an embodiment, a method of forming a calibration curve is provided. The method includes ion-implanting different doses of an impurity into a plurality of first samples, measuring an intensity of photoluminescence deriving from the impurity by a photoluminescence spectroscopy for the first samples and a second sample made of the same semiconductor. Based on the amount of implanted impurity, the intensity of the photoluminescence, and a concentration of the impurity contained in the second sample measured by a method other than the photoluminescence spectroscopy, a calibration curve is formed.
Globalwafers Japan Co. | Date: 2014-07-10
A silicon single crystal manufacturing method includes: applying a transverse magnetic field to a melt of polysilicon with a carbon concentration of at most 1.010
Globalwafers Japan Co. | Date: 2014-07-31
A silicon wafer is manufactured by subjecting a silicon wafer sliced from a silicon single-crystal ingot grown by the Czochralski process to a rapid thermal process in which the silicon wafer is heated to a maximum temperature within a range of 1300 to 1380 C., and kept at the maximum temperature for 5 to 60 seconds; and removing a surface layer of the wafer where a semiconductor device is to be manufactured by a thickness of not less X [m] which is calculated according to the below equations (1) to (3):
Nakagawa S.,GlobalWafers Japan Co. |
Kashima K.,GlobalWafers Japan Co.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2014
The calibration curve for the carbon concentration in silicon epitaxial layers was obtained by photo-luminescence spectroscopy after carbon ion implantation and electron irradiation. Low carbon concentrations on the order of 1014 atoms/cm3 affected properties such as the on-resistance and carrier lifetime of insulated gate bipolar transistors (IGBTs). We focused on carbon impurities because interstitial carbon can form complexes, such as complexes of interstitial and substitutional carbon (Ci-Cs) and of interstitial carbon and oxygen (Ci-Oi), which produce deep levels in the energy band gap. To verify the effects of carbon impurities separately from those of oxygen impurities, oxygen-free silicon epitaxial layers were studied. The carbon concentration in silicon epitaxial wafers was evaluated quantitatively by using our calibration curve. Carbon ion implantation and photoluminescence spectrum measurements were performed to obtain the slope of the calibration curve. In addition, secondary ion mass spectrometry measurement gave absolute carbon concentration against photo-luminescence intensity for fixing the calibration curve. The calibration curve was used to determine the carbon concentration for each IGBT. Carbon impurity concentrations as low as 1014 atoms/cm3 in silicon epitaxial layers lowered device performance. Therefore, decreasing the carbon impurity concentration is essential for improving the performance of advanced IGBTs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Kamiyama E.,Okayama Prefectural University |
Vanhellemont J.,Ghent University |
Sueoka K.,Okayama Prefectural University |
Araki K.,GlobalWafers Japan Co. |
Izunome K.,GlobalWafers Japan Co.
Applied Physics Letters | Year: 2013
When pulling large diameter Si crystals from a melt close to the Voronkov criterion, small changes in pulling speed and thermal gradient can lead to the formation of voids leading to detrimental pits on the polished wafer surface. The creation of voids is mainly due to the lowering of the vacancy formation energy due to increased thermal compressive stress. The small size and low density of the formed voids when pulling crystals close to the Voronkov criterion conditions are a challenge for wafer surface inspection tools and possible solutions are discussed. © 2013 American Institute of Physics.