Abstract
The behavior of point defects was visualized in lightly and heavily boron (B)-doped Czochralski-silicon (CZ-Si) crystals by employing a special growth technique, namely, rapidly cooling a growing crystal after it is detached from the Si melt. In the case of crystal growth with a high pulling rate, an anomalous oxygen precipitation (AOP) region dominated by vacancies appeared, whereas in the case of crystal growth with a low pulling rate, a dislocation loop region dominated by self-interstitials appeared. In the crystals cooled rapidly after halting growth for several hours, self-interstitials flowed into the AOP region and dislocation loop regions formed and expanded, while the AOP region shrunk due to diffusion of excess vacancies to the crystal surface and void regions. These transient changes in the point defect distribution were reproduced using a point defect simulator. Defect regions related to self-interstitials could not be confirmed in the heavily B-doped crystals with resistivities of 10 mΩcm or less, where the void- and oxidation-induced stacking fault (OSF)-ring regions disappeared completely at the center of the crystal. These results show that the behaviors of point defects in heavily doped CZ-Si crystals with various impurities are important research subjects in relation to future advanced power applications.
Highlights
Point defects in Czochralski (CZ)-Si crystals form aggregates, such as voids[1,2] and dislocation clusters,[3] and secondary defects, such as oxygen precipitates, stacking faults, and/or dislocations due to reactions with oxygen, carbon, or nitrogen
The thermal equilibrium concentrations of CÃv and CÃi are expressed in Eq (4) by using the formation energies of Efv for vacancies and Efi for self-interstitials
This simulator uses the physical parameters of the equilibrium concentrations and diffusion rates of vacancies and self-interstitials that were optimized by Nishimoto,[9,10] who used a generic algorithm method[32] and simulated annealing[33]; the V-I boundary, where vacancies and self-interstitials are in balance in the growing CZ-Si crystals, are reproduced as accurately as possible
Summary
Point defects in Czochralski (CZ)-Si crystals form aggregates, such as voids[1,2] and dislocation clusters,[3] and secondary defects, such as oxygen precipitates, stacking faults, and/or dislocations due to reactions with oxygen, carbon, or nitrogen. Since these defects directly affect the performance and characteristics of semiconductor devices, it is important to understand and control the behavior of point defects during CZ-Si crystal growth. (Received December 9, 2019; accepted May 5, 2020; published online May 20, 2020)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
