摘要

At present, almost all Si single crystals for solar cell applications are grown by the Czochralski (Cz) method. In the Cz method, the oxygen from the quartz crucible is dissolved into Si melt while growing a Si single crystal. The average concentration of oxygen in the Si lattice is in the range of 5 x 10(17)similar to 1 x 10(18) atoms/cm(3) at an interstitial site of a diamond structure of Si. The most prevalent impurity atom in a Cz-Si single crystal is oxygen, which plays many roles in a Si wafer for the semiconductor and solar industry. In particular, Thermal Donors (TDs) are composed of a Si and oxygen compound and are generated by slow cooling in the temperature range of 350 similar to 500 degrees C. TDs influence the resistivity of a Si wafer. The generation of TDs along the axial length of a Si crystal changes due to different thermal history along the axial direction of a Si single crystal. The various tests to change the amount of TDs were conducted by modifying hardware and adjusting software. The resistivity was measured before Thermal Donor Annealing (TDA). In the case of adaption of a cooling water jacket (CWJ) inside of a grower, resistivity before TDA decreased significantly.

  • 出版日期2016-3