ᚑくᄢቇℂᎿቇ⎇ⓥႎ๔
J. Fac. Sci. Tech., Seikei Univ.
Vol.46 No.2 (2009) pp.113-115
㧔․೎⎇ⓥ⾌ߦଥࠆ⺰ᢥ㧕ᄙ⚿᥏ࠪ࡝ࠦࡦᄥ㓁㔚ᳰߩ᳓⚛ࡄ࠶ࠪࡌ࡯࡚ࠪࡦଦㅴࡊࡠ࠮ࠬ㥲⮮ ᵗม 㧘㐷㚍 ᱜ 㧘૒㊁ ⧷ਯ A Study on Enhanced Hydrogenation Process for Multi-crystalline Silicon Solar Cells
Yoji SAITO*1㧘Tadashi MOMMA 㧘Hideyuki SANO ABSTRACT㧦Most of commercial solar cells are based on polycrystalline silicon substrates. Latticedefects, however, are included in polycrystalline silicon substrates, and degrade the electricalcharacteristics of the solar cells. Hydrogen passivation process is usually performed to reduce theelectrically active defect levels at temperatures between 250C and 300C for hours. In this study, we
found that the electrical characteristics of the solar cells with polycrystalline silicon substrates would
largely depend on a bias voltage during the hydrogenation process. With increase of the value of thenegative bias voltage, short circuit current, Isc, and the efficiency increase. The electrical characteristicsof the solar cells are apparently improved at a reverse bias voltage near 0.6V during the hydrogenation
process. The increase of Isc and the efficiency is considered to be induced by the passivation of thedefect levels located near the pn junction with the diffused hydrogen. The phenomena are likely due tothe existence of positively-ionized hydrogen, H+. The H+ ions can be accelerated from the surface into
the bulk by the electric field with the negative bias. The possibility of the H+ ions in the bulk silicon has
been predicted in the previous reports.
Keywords㧦multi-crystalline silicon, hydrogen diffusion, defect passivation, hydrogen plasma(Received September 29, 2009) ᄙ⚿᥏ࠪ࡝ࠦࡦᄥ㓁㔚ᳰߩ᳓⚛ࡄ࠶ࠪࡌ࡯࡚ࠪࡦᎿ⒟㧝㧚✜ ⺰ߪ㧘⃻࿷㧘᳓⚛ࠍ฽߻ࠪ࡝ࠦࡦ⓸ൻ⤑ࠍၸⓍᓟ㧘ᾲಣℂ ⃻࿷㧘ᄥ㓁㔚ᳰߩᄢㇱಽߦߪᲧセ⊛቟ଔߢ㧘቟ቯߒߚߢಽ⸃ߔࠆ㓙ߦ᡼಴ߐࠇࠆ᳓⚛ߩၮ᧼߳ߩ᜛ᢔߦࠃࠅⴕᄌ឵ല₸߇ᓧࠄࠇࠆᄙ⚿᥏ࠪ࡝ࠦࡦᄥ㓁㔚ᳰ߇೑↪ߐࠇࠊࠇߡ޿ࠆ‫ߒ߆ߒޕ‬㧘ߘߩ⤑ߩಽ⸃᧦ઙߩ▸࿐ߪ㒢ࠄࠇߡ޿ࠆ‫ߒ߆ߒޕ‬㧘ᄙ⚿᥏ၮ᧼ߦ߅޿ߡߪ㧘☸⇇ߩߺߥࠄߡ߅ࠅ㧘᳓⚛ࡄ࠶ࠪࡌ࡯࡚ࠪࡦߩⷰὐ߆ࠄ⷗ࠆߣ㧘ዉ౉ߕ☸ౝߦ߽ᩰሶᰳ㒱߇ሽ࿷ߒ㧘න⚿᥏ᄥ㓁㔚ᳰߣᲧセߒ᳓⚛㊂߿ᷓߐಽᏓߦ㑐ߒߡචಽߥಣℂߢߪߥ޿ߣ⠨߃ࠄߡᕈ⢻߇ૐ޿ේ࿃ߣߥߞߡ޿ࠆ‫ޕ‬ᩰሶᰳ㒱ߪࠪ࡝ࠦࡦᧂࠇࠆ‫ޕ‬⚿วᚻߢ޽ࠅ㧘⑌೙ᏪߦḰ૏ࠍᒻᚑߔࠆߚ߼㧘☸⇇ઃㄭ ߣߎࠈߢᢥ₂ߦࠃࠆߣ㧘ၮ᧼ਛߩ᳓⚛߇޽ࠆ৻ቯߩ⏕ߢߪࡐ࠹ࡦࠪࡖ࡞ࡃ࡝ࠕࠍᒻᚑߒߡ㔚ᵹ⚻〝ࠍ⁜ߊߒ㧘₸ߢ H+ߣߥࠅሽ࿷ߔࠆߎߣ߇ផቯߐࠇߡ޿ࠆ 1)‫⎇ᧄޕ‬ⓥ☸ౝߢߪࠠࡖ࡝ࠕߩౣ⚿วߦࠃࠅ⊒㔚ߒߚ㔚ᵹࠍ㔚ᳰౝߢߪ㧘ᄥ㓁㔚ᳰߦㅒࡃࠗࠕࠬࠍශടߒߥ߇ࠄ᳓⚛ൻಣℂㇱߢᶖ⾌ߒߡߒ߹޿㧘⚿ᨐߣߒߡᄌ឵ല₸߇ૐਅߔࠆ‫ޕ‬ࠍⴕ߁ߎߣߦࠃࠅ㧘⴫㕙߆ࠄౝㇱߦะߌߡല₸⦟ߊ᳓⚛

ᩰሶᰳ㒱ࠍቢోߦߥߊߔߎߣߪᛛⴚ⊛ߦ࿎㔍ߥߚ߼㧘ታࠍᷓߊ᜛ᢔߐߖࠆߎߣ߇ߢ߈ࠆߩߢߪߥ޿߆ߣ⠨߃ߚ‫ޕ‬㓙ߦߪ㧘᳓⚛ේሶࠍᰳ㒱ㇱಽߦઃ⌕ߐߖ㧘ᧂ⚿วᚻࠍߥࡃࠗࠕࠬ㔚࿶߇㧘㔚᳇⊛․ᕈ߿᳓⚛᜛ᢔ߳෸߷ߔᓇ㗀ࠍߊߒ㧘⚿ᨐߣߒߡᰳ㒱Ḱ૏ࠍ௛߆ߥߊߔࠆᣇᴺ߇↪޿ࠄ⺞ߴߚ‫ޕ‬ࠇࠆ‫ߣࡦ࡚ࠪ࡯ࡌࠪ࠶ࡄࠍࠇߎޕ‬๭߱‫ޕ‬
*1
*2
*3

ᚑくᄢቇℂᎿቇㇱࠛ࡟ࠢ࠻ࡠࡔࠞ࠾ࠢࠬቇ⑼ᢎ᝼
yoji@st.seikei.ac.jp㧘Professor,Department of Mechanical and Electrical EngineeringᚑくᄢቇℂᎿቇㇱࠛ࡟ࠢ࠻ࡠࡔࠞ࠾ࠢࠬቇ⑼ഥᚻᚑくᄢቇᄢቇ㒮Ꮏቇ⎇ⓥ⑼㔚᳇㔚ሶᎿቇኾ᡹

㧞㧚ታ㛎ᣇᴺ
 30mm23mm ߦࠞ࠶࠻ߒߚᛶ᛫₸ 1.9ǡcm ߩ p ဳᄙ⚿㧙㧙᥏ Si ၮ᧼ࠍ↪޿ߚ‫ޕ‬1000͠㧘3h ᳓⫳᳇㉄ൻߒ㧘㉄ൻ⤑ࠍᒻᚑᓟ㧘ࡈࠜ࠻࡝࠰Ꮏ⒟ߢࡄ࠲࡯࠾ࡦࠣࠍⴕߞߚ‫࡝ޕ‬
ࡦࠍ 1000͠㧘40 ಽ㑆ᾲ᜛ᢔߒ㧘⴫㕙෸߮ⵣ㕙ߦ Al 㔚ᭂ ᳓⚛ൻߦࠃࠅ᳓⚛Ớᐲ߇ߤߩࠃ߁ߦᄌൻߒߡ޿ࠆ߆⺞ߴࠆߚ߼㧘᳓⚛ൻ೨ᓟߢ FTIR ᷹ቯࠍⴕߞߚ‫ޕ‬᳓⚛ൻߦࠃࠆๆ෼ߩჇടಽࠍࠬࡍࠢ࠻࡞ߣߒߡ࿑ 2 ߦ␜ߔ‫ޕ‬ࠍᒻᚑߒ㧘ᄥ㓁㔚ᳰ⹜ᢱࠍ૞⵾ߒߚ‫ޕ‬

2017cm-1 ઃㄭߦ Si-H ⚿วߦࠃࠆๆ෼ࡇ࡯ࠢ߇᷹ⷰߐࠇ㧘 ࠬࡄ࠶࠲ⵝ⟎ࠍᡷㅧߒߚⵝ⟎ߦᄥ㓁㔚ᳰ⹜ᢱࠍዉ౉ߒ

ㅒࡃࠗࠕࠬශടߦࠃࠅ㧘Si-H ỚᐲߩჇᄢ߇⏕⹺ߢ߈ߚ‫ޕ‬ߡ㧘200͠㨪300͠ߩ▸࿐ߢࡊ࡜࠭ࡑ᳓⚛ൻಣℂࠍⴕߞߚ‫ޕ‬ ߐࠄߦ㧘ಽశᗵᐲ․ᕈࠍ⺞ߴߚ‫ࡦࠦ࡝ࠪޕ‬ၮ᧼ߢߪ㧘ߎߩᤨ㧘ᄥ㓁㔚ᳰߦࡃࠗࠕࠬ㔚࿶ࠍශടߒߚ‫ޕ‬᳓⚛ൻಣ᷹ቯᵄ㐳▸࿐ߦ߅޿ߡᵄ㐳߇㐳޿߶ߤశ߇ᷓߊଚ౉ߔࠆ

ℂ೨ᓟߢ I-V ․ᕈ㧘ಽశᗵᐲ᷹ቯ㧘FTIR㧔⿒ᄖๆ෼㧕ࠬߚ߼㧘㔚ᵹߩᵄ㐳ଐሽᕈ߆ࠄߤߩㇱಽߩᰳ㒱߇ࡄ࠶ࠪࡌࡍࠢ࠻࡞ࠍ᷹ቯߒߚ‫ޕ‬࡯࡚ࠪࡦߐࠇߚ߆ផቯߢ߈ࠆ‫ޕ‬࿑ 3 ߦㅒࡃࠗࠕࠬࠍශടߒߥ߇ࠄ᳓⚛ൻಣℂࠍⴕߞߚ⹜ᢱ߅ࠃ߮ಣℂ೨ߩಽశᗵ㧟㧚ታ㛎⚿ᨐ߅ࠃ߮ᬌ⸛ ᐲࠬࡍࠢ࠻࡞ࠍ␜ߔ‫ޕ‬᳓⚛ൻಣℂߦࠃࠅ㧘శๆ෼ଥᢙߩዊߐ޿⿒ᄖ㗔ၞߦ߅޿ߡ㔚ᵹ߇ᄢ߈ߊჇടߒߡ޿ࠆ‫ߎޕ‬ ၮ᧼᷷ᐲ 300͠ߢ᳓⚛ൻಣℂࠍⴕߞߚᄥ㓁㔚ᳰߦ߅ߌࠇࠄ߆ࠄ㧘ㅒࡃࠗࠕࠬ㔚࿶ࠍශടߒߥ߇ࠄ᳓⚛ൻߔࠆߎ

ࠆಣℂലᨐߩࡃࠗࠕࠬ㔚࿶ଐሽᕈࠍ㧘ಣℂ೨ᓟߩ⍴⛊㔚ߣߦࠃࠅ㧘ࠃࠅᄙߊߩ᳓⚛ࠍࠃࠅᷓߊ᜛ᢔߐߖ㧘ല₸⊛ᵹ Isc Ყ߅ࠃ߮⊒㔚ല₸Ყߢ㧘࿑ 1 ߦ␜ߔ‫ߢߎߎޕ‬㧘᷹ߥᰳ㒱ࡄ࠶ࠪࡌ࡯࡚ࠪࡦലᨐࠍᓧࠆߎߣ߇ߢ߈ߚߣ⠨߃ቯᤨߩశᒝᐲߪ 15mWcm ߢ޽ߞߚ‫ߚ߹ޕ‬㧘ಣℂ೨ߩല
-2₸ߪ 2㨪4%ߣૐߊ㧘߹ߚ߫ࠄߟ߈߇޽ߞߚ‫ޕ‬࿑ 1 ߦ߅޿ߡ㧘ࡃࠗࠕࠬ㔚࿶߇-0.6V㨪-0.4V ߩ▸࿐ߢ Isc ߅ࠃ߮ലࠄࠇࠆ‫ޕ‬
0.09


ߒߡሽ࿷ߔࠆ᳓⚛ߩ᜛ᢔ߇ଦㅴߐࠇ㧘ᰳ㒱ࡄ࠶ࠪࡌ࡯ࠪ

࡚ࡦ߇ߥߐࠇߚߚ߼ߣ⠨߃ࠄࠇࠆ‫ޕ‬ ৻ᣇ㧘㗅ࡃࠗࠕࠬ㔚࿶ߦ߅޿ߡߪ㧘ㅒߦ․ᕈ߇ᖡൻߔ

ࠆߎߣ߇ࠊ߆ߞߚ‫ߪࠇߎޕ‬㧘⴫㕙ઃㄭߦ㜞Ớᐲߩ᳓⚛߇⇐߹ࠅ㧘ㅒߦᰳ㒱ࠍ↢ߓࠆߚ߼ߣᕁࠊࠇࠆ 3)‫ޕ‬

Spectral response [A/W]₸߇ᄢ᏷ߦჇടߔࠆߎߣ߇ࠊ߆ߞߚ‫ ߪࠇߎޕ‬H+ࠗࠝࡦߣ 㪉㪇㪇

0.08

Before hydrogenation
After hydrogenation

0.070.060.050.04400㪈㪌㪇㪚㪿㪸㫅㪾㪼㩷㩿㩼㪀㪈㪇㪇 㪌㪇㪠㫊㪺
㪜㪽㪽㫀㪺㫀㪼㫅㪺㫐

500

600

Wavelength [nm]700800㪇࿑㧟 ᳓⚛ൻ೨ᓟߩಽశᗵᐲࠬࡍࠢ࠻࡞㧔8㧩8㧕㪄㪌㪇㧠㧚⚿ ⺰㪄㪈㪇㪇㪄㪇㪅㪍㪄㪇㪅㪋㪄㪇㪅㪉㪙㫀㪸㫊㩷㫍㫆㫃㫋㪸㪾㪼㩷㩿㪭㪀㪇㪇㪅㪉 ᄙ⚿᥏ࠪ࡝ࠦࡦᄥ㓁㔚ᳰߦㅒࡃࠗࠕࠬࠍශടߒߥ߇ࠄ࿑㧝 ⍴⛊㔚ᵹ㧘ല₸ߩჇട₸ߩࡃࠗࠕࠬ㔚࿶ଐሽᕈ
᳓⚛ൻಣℂࠍⴕ߁ߎߣߦࠃࠅ㧘ല₸⊛ߥᰳ㒱ࡄ࠶ࠪࡌ࡯
0.007



0.006
Absorbance0.005
0.00460min࡚ࠪࡦࠍⴕ߁ߎߣ߇ߢ߈ߚ‫⿒ޕ‬ᄖๆ෼ࠬࡍࠢ࠻࡞߿ಽశ

V=0[V]
V=-0.6[V]ᗵᐲ᷹ቯ߆ࠄ㧘ࡃࠗࠕࠬ㔚࿶ශടߦࠃࠅ⴫㕙߆ࠄౝㇱ߳᳓⚛ࠍࠃࠅᄙߊ߆ߟᷓߊ᜛ᢔߐࠇߡ޿ࠆߎߣࠍ⏕⹺ߒߚ‫ޕ‬

0.0030.002

 0.001   0 2000ࡃࠗࠕࠬ㔚࿶ߦࠃࠆലᨐߪၮ᧼ౝㇱߦሽ࿷ߔࠆ᳓⚛ࠗࠝࡦߦࠃࠆ߽ߩߣ⠨߃ߡ޿ࠆ‫ޕ‬

2010

2020

2030

2040

2050

Wavenumber [1/cm]

2060

2070

2080

࿑㧞 ᳓⚛ൻಣℂߦࠃࠆ⿒ᄖๆ෼ࠬࡍࠢ࠻࡞ᄌൻ㧙㧙ෳ⠨ᢥ₂1)

S. Darwiche, M. Nikravech, D. Morvan, J. Amouroux

and D. Ballutaud, Solar Energy Materials and SolarCells, 91, Issues 2-3, 23, p.195 (2007).

2)

Y. Saito and Y. Sano, Proc. 2009MRS, 1153, A18-01

3)

S. Martinuzzi and I. Perichaud, Solar Energy Materials(2009)

and Solar Cells, 72, p.343 (2003)㧙㧙