Observation on Defects in Poly-Si Films Prepared by RTCVD Under Nonideal Conditions

• Published in: Journal of electronic materials Vol. 39; no. 6; pp. 732 - 737
• Main Authors: Ai, Bin, Shen, Hui, Deng, You-Jun, Liu, Chao, Liang, Xue-Qin
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Boston Springer US 01.06.2010; Springer; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemical vapor deposition; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects; Defects and impurities in crystals; microstructure; Defects and impurities: doping, implantation, distribution, concentration, etc; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Linear defects: dislocations, disclinations; Materials Science; Methods of deposition of films and coatings; film growth and epitaxy; Optical and Electronic Materials; Physics; Polycrystals; Solid State Physics; Stacking faults and other planar or extended defects; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Transmission electron microscopy; dislocations; twin crystal; stacking faults; polycrystalline silicon; chemical vapor deposition; foreign substrate; transmission electron microscopy; Defects; Second order; Polycrystals; Etching; Thin films; Optical microscopy; Mismatch lattice; Stress effects; Dislocation line; Crystal twin; Stacking faults; Twinning; Quartz; Dislocations; CVD; Ordered crystals; Experimental result; Transmission electron microscopy; Silicon oxides; Growth mechanism; Dislocation arrays; Polysilicon; Dislocation loops
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-010-1145-0

Polycrystalline silicon (poly-Si) thin films were deposited on quartz substrates by rapid thermal chemical vapor deposition (RTCVD) under nonideal conditions. Then, crystallographic defects in the poly-Si films were investigated by using transmission electron microscopy (TEM) and optical microscopy combined with defect etching. We found that as-deposited poly-Si films contain a lot of twin crystals, including first-order, second-order, third-order, and higher-order twinned crystals. Besides twinned crystals, stacking faults, dislocations, dislocation nets, dislocation loops, extended dislocations, and dislocation line arrays were also found. Finally, the origins of the defects were analyzed, being attributed to the peculiarities of the RTCVD-quartz growth system, stress caused by lattice and thermal mismatch, a huge temperature ramp, and nonideal deposition conditions. Although our experimental results cannot represent the crystallographic quality of poly-Si films prepared by RTCVD, they at least indicate what kinds and how many defects exist in poly-Si films when deposition conditions severely deviate from the optimum.