Effects of B{sub 18}H{sub x}{sup +} and B{sub 18}H{sub x} dimer ion implantations on crystallinity and retained B dose in silicon
- Renesas Electronics Corporation, 751 Horiguchi, Hitachinaka, Ibaraki 312-8504 (Japan) and Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530 (Japan)
The effects of B{sub 18}H{sub x}{sup +} and B{sub 18}H{sub x} dimer ion (B{sub 36}H{sub y}{sup +}) implantations on Si crystallinity and the retained B dose in Si were investigated using B{sub 18}H{sub x} bombardment and compared with the effects of B{sup +} implantation. Crystallinity was estimated for the implantation dose using molecular dynamic simulations (MDSs) and was quantified using the optical thickness obtained from spectroscopic ellipsometry. The authors focused on the crystallinity at a low B dose and compared the amorphized zones predicted by MDS for B{sub 18}H{sub x}{sup +} implantation with those measured using transmission electron microscopy; the predicted and measured results were in reasonable agreement. The authors then used their understanding of B{sub 18}H{sub x} bombardment to discuss the process for the generation of larger amorphized zones and thicker amorphized layers, as observed in B{sub 36}H{sub y}{sup +} implantation. The retained B dose and the sputtering were examined with secondary ion mass spectroscopy, focusing on a comparison of the retained B and the sputtering of Si and SiO{sub 2} surfaces. The retained B dose was lower for B{sub 18}H{sub x}{sup +} and B{sub 36}H{sub y}{sup +} implantations, with and without surface SiO{sub 2}, than for B{sup +} implantation, although no sputtering was observed. The reduction of the retained B dose was more severe in the samples with SiO{sub 2}. The origin of the differences between Si and SiO{sub 2} surfaces was considered to be Si melting; this was predicted by the MDSs, and observed indirectly as flat B profiles in the Si region. To examine the effects of both crystallinity and retained B dose on the electrical characteristics, the sheet resistance (R{sub S}) was measured. The R{sub S} for B{sub 18}H{sub x}{sup +} implantation was lower than that for B{sup +} implantation at both B doses studied. Additionally, the B{sub 36}H{sub y}{sup +} implantation under conditions that produced a thicker amorphized layer led to lower R{sub S} than B{sub 18}H{sub x}{sup +} implantation. These results indicate that both the amorphized layer and the amorphized zone contribute to the activation of more B atoms.
- OSTI ID:
- 22051364
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 30, Issue 1; Other Information: (c) 2012 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BORON COMPOUNDS
BORON IONS
DIMERS
DOSES
ELLIPSOMETRY
ION IMPLANTATION
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
MELTING
MOLECULAR DYNAMICS METHOD
SILICON
SILICON OXIDES
SPUTTERING
TRANSMISSION ELECTRON MICROSCOPY