Effect of stress on the evolution of mask-edge defects in ion-implanted silicon

Olson, C. R.; Kuryliw, E.; Jones, Brian E.; Jones, K. S.

doi:10.1116/1.2162566

Cited by 23 publications

(20 citation statements)

References 6 publications

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“…The ͓110͔ stress ͑ ͓110͔ ͒ was calculated using the ͓110͔ Young's modulus of Si near ϳ500°C ͑ϳ1.61ϫ 10 11 Pa͒, the wafer halfthickness, and the local radius of curvature as presented elsewhere. 10,11 Maximum repeatable stresses of 1.5± 0.1 GPa were attained. Specimens were annealed at 525°C in N 2 ambient for 0.7-3.2 h. Stress-free, tensile, and compressive specimens were annealed simultaneously for each anneal time.…”

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confidence: 95%

Solid phase epitaxy in uniaxially stressed (001) Si

Rudawski

Jones

Gwilliam

2007

Applied Physics Letters

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The effect of ͓110͔ uniaxial stresses up to 1.5 GPa on defect nucleation during solid phase epitaxy of amorphous ͑001͒ Si created via ion implantation was examined. The solid phase epitaxial regrowth velocity was slowed in compression. However, in tension, the velocity was unaffected. Both compression and tension resulted in an increase in regrowth defects compared to the stress-free case. The defects in compression appear to arise from roughening of the crystallizing interface whereas in tension it is proposed that reorientation of crystallites near the initial amorphous/ crystalline interface is responsible for defect formation. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2801518͔ Solid phase epitaxy ͑SPE͒ in amorphous ͑␣͒ Si created via ion implantation produces enhanced dopant activation and shallower junctions. 1 However, stresses found during typical device fabrication may influence the SPE process. 2,3 Early investigations revealed exponential enhancement of the ͓001͔ SPE using hydrostatic pressure while subsequent investigations revealed uniaxial stress in the plane of the regrowing ␣/crystalline interface caused smaller changes to SPE rates. [4][5][6] In-plane compression also caused significant roughening of the regrowing ␣/crystalline interface. 7 This is significant since interfacial roughening is known to cause SPE-related defect formation. 8,9 However, while BarvosaCarter et al. 7 quantified and modeled the roughness of the regrowing interface, they did not quantify the resulting defects or examine tensile stresses. Furthermore, the stresses used were fairly small in magnitude ͑Ͻ0.5 GPa͒ and the stresses present in Si-based technology can be ϳ1 GPa or more. 2 Thus, the goal of this study is to examine the effect of very high uniaxial ͓110͔ stresses on SPE in ͑001͒ Si.For this study, 50-m-thick polished ͑001͒ Si wafers were used. The specimens were first Si + implanted at 50 and 200 keV with doses of 1.0ϫ 10 15 cm −2 and subsequently As + implanted at 300 keV to a dose of 1.8ϫ 10 15 cm −2 . Samples were cleaved along ͗110͘ directions into ϳ0.3ϫ 1.8 cm 2 strips. Stress was applied by bending and inserting the strips into slots in a quartz tray spaced ϳ1.5 cm apart. A Philtec laser displacement measurement system accurate to 1 m measured the local radius of curvature along the strips. The bent strips were symmetric and parabolic in shape with the smallest radius of curvature at midlength. The ͓110͔ stress ͑ ͓110͔ ͒ was calculated using the ͓110͔ Young's modulus of Si near ϳ500°C ͑ϳ1.61ϫ 10 11 Pa͒, the wafer halfthickness, and the local radius of curvature as presented elsewhere. 10,11 Maximum repeatable stresses of 1.5± 0.1 GPa were attained. Specimens were annealed at 525°C in N 2 ambient for 0.7-3.2 h. Stress-free, tensile, and compressive specimens were annealed simultaneously for each anneal time. Upon removal from the quartz tray after annealing, the specimens exhibited no detectable radii of curvature ͑ӷ2.0 m͒ indicating no measurable plastic strain. Regrowth of the ␣-Si layers was ex...

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Solid phase epitaxy in uniaxially stressed (001) Si

Rudawski

Jones

Gwilliam

2007

Applied Physics Letters

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“…Finally, stress can influence the shape of a regrowing ␣/crystalline interface and it is worthwhile to consider this as stress from trench structures can be significant. 14,15 However, because both SiO 2 -filled and SiO 2 -free trench structures exhibited similar regrowth interfaces, the observations are likely not stress-related.…”

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Effect of Oxide on Trench Edge Defect Formation in Ion-Implanted Silicon

Burbure

Rudawski

Jones

2007

Electrochem. Solid-State Lett.

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An investigation of the defects that form near oxide-filled trenches during solid-phase epitaxy of amorphous silicon produced by ion implantation was conducted. It was observed that defects form near the trench edge after recrystallization. Defect formation resulted from pinning of the initial amorphous/crystalline interface at the trench edge and regrowth proceeded until triangular amorphous regions bound by the surface, trench, and ͑111͒ plane were formed. Regrowth of the triangular regions then proceeded along the ͓111͔ direction and was highly defective after recrystallization. Annealing of specimens with oxide-free trenches produced smaller defective regions compared to oxide-filled trenches. © 2007 The Electrochemical Society. ͓DOI: 10.1149/1.2719597͔ All rights reserved.Manuscript submitted December 20, 2006; revised manuscript received February 7, 2007. Available electronically March 28, 2007. It has been known that stress from oxide ͑SiO 2 ͒ trench structures in ion-implanted silicon ͑Si͒ wafers can lead to the formation of defects near trench edges, which may cause device degradation or failure.1-3 These defects typically form during high-temperature processing but may also occur during solid-phase epitaxy ͑SPE͒ of amorphous ͑␣͒ Si. It is known that SPE in bulk Si can lead to the formation of ͕111͖ stacking faults as well as other secondary defects. 4 More relevantly, regrowth of two-dimensional ␣-Si regions via simultaneous SPE of two orthogonal fronts with different crystal orientations in patterned wafers can produce defects near the mask-edge. [5][6][7] However, the formation of defects during SPE near trench structures is not well understood. In the case of high-dose arsenic ͑As͒ implantation well in excess of solubility, trench-edge defects were observed as a result of regrowth interface pinning during SPE.8 Furthermore, As + -implantation is known to cause secondary defect formation at the projected range of implantation, and it is unclear whether the implanted species affects trench-edge defect formation.9,10 Another explanation for trench-edge defects is the migration of point defects to regions of high stress generated by patterned structures, but this not thought to be related to SPE.11 Thus, the goal of this study is to investigate the formation of trench-edge defects during SPE in Si wafers amorphized by Si + implantation. For this study, 300 mm ͑001͒ wafers were patterned with SiO 2 -filled trenches ϳ400 nm deep. After patterning, the wafers were implanted with Si + at energies of 10-80 keV and doses of 1 ϫ 10 15 to 1 ϫ 10 16 cm −2 . This produced ␣-Si layer depths ranging from 20 to 160 nm. Anneals were performed at 700 or 950°C using rapid thermal annealing ͑RTA͒. All anneals were preceded by a 10 s soak at 600°C. Transmission electron microscopy ͑TEM͒ was used to image ␣-Si regrowth in the vicinity of trench edges. Both crosssectional TEM ͑XTEM͒ and plan-view TEM ͑PTEM͒ were used for this study. Imaging was performed using weak-beam dark-field ͑WBDF͒ or on-axis bright-field ͑BF͒ con...

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“…However, it is important to consider the role that applied stress may have on the SPEG process in patterned material, since the presence of stresses of substantial magnitude is ubiquitous in current Si-based device fabrication (Hu, 1991). Interestingly, extensive prior work showed that the application of different forms of mechanical stress during SPEG could alter the morphology of the evolving growth interface thus favoring or impeding mask-edge defect formation (Olson et al, 2006;Rudawski et al, 2006Rudawski et al, , 2008aRudawski et al, , 2009bShin et al, 2001a,b,c). Specifically, when uniaxial tension was applied along the in-plane [110] direction during SPEG, the impingement of the two portions of the growth interface was retarded, which resulted in defect-free growth (Olson et al, 2006;Rudawski et al, 2006Rudawski et al, , 2008aRudawski et al, , 2009b.…”

Section: Stress Effectsmentioning

confidence: 94%

“…Interestingly, extensive prior work showed that the application of different forms of mechanical stress during SPEG could alter the morphology of the evolving growth interface thus favoring or impeding mask-edge defect formation (Olson et al, 2006;Rudawski et al, 2006Rudawski et al, , 2008aRudawski et al, , 2009bShin et al, 2001a,b,c). Specifically, when uniaxial tension was applied along the in-plane [110] direction during SPEG, the impingement of the two portions of the growth interface was retarded, which resulted in defect-free growth (Olson et al, 2006;Rudawski et al, 2006Rudawski et al, , 2008aRudawski et al, , 2009b. In contrast, when uniaxial compression was applied along the in-plane [110] direction during SPEG, the impingement of the two portions of the growth interface was enhanced, which resulted in defective growth (Olson et al, 2006;Rudawski et al, 2006Rudawski et al, , 2008aRudawski et al, , 2009b.…”

Section: Stress Effectsmentioning

confidence: 96%