http://support.spring8.or.jp/Report_JSR/PDF_JSR_31A/2019A1766.pdf

2019A1766BL46XU㑄⛣㔠ᒓ㓟໬≀㸭⤖ᬗࢩࣜࢥࣥᵓ㐀ኴ㝧㟁ụࢹࣂ࢖ࢫࡢࣂࣥࢻ᥋⥆ࡢỴᐃ㸸◳ X ⥺ග㟁Ꮚศගἲ࡟ࡼࡿ໬Ꮫ⤖ྜ≧ែホ౯Hard X-ray Photoelectron Spectroscopy Analysis of Band Alignment inTransition Metal Oxide/cSi Contact Cell Structures⚄ᒸ Ṋᩥ a,b, Lee Hyunjub, すཎ 㐩ᖹ a, 㔠஭ ⓡ㍤ a, ཎ ▱ᙪ b, ⬥⏣ 㝣 b,⏫⏣ ⱥ᫂ c, ኱ୗ ⚈㞝 b, ᑠ᳚ ཌᚿ a a,b
Takefumi Kamioka , Lee Hyunjub, Tappei Nishiharaa, Hiroki Kanaia, Tomohiko Harab, Riku Wakitab,Hideaki Machidac, Yoshio Ohshitab, Atsushi Oguraaa᫂἞኱Ꮫ, b ㇏⏣ᕤᴗ኱Ꮫ, c Ẽ┦ᡂ㛗ᰴᘧ఍♫aMeiji University, bToyota Technological Institute, cGas-Phase Growth Ltd.
 㑄⛣㔠ᒓ㓟໬≀㸦TMO㸧ࢆ⏝࠸ࡓ࢟ࣕࣜ࢔㑅ᢥࢥࣥࢱࢡࢺ㸦CSC㸧ᵓ㐀ࢆ᭷ࡍࡿḟୡ௦⤖ᬗ Siኴ㝧㟁ụࢹࣂ࢖ࢫ࡟࠾࠸࡚ࠊᇙࡶࢀࡓ⏺㠃ࡢ໬Ꮫ⤖ྜ≧ែࢆ◳ X ⥺ග㟁Ꮚศග㸦HAXPES㸧࡛ホ౯ࡍࡿࠋᮏ◊✲࡛ࡣࠊ㟁Ꮚ㑅ᢥࢥࣥࢱࢡࢺ࡜ࡋ࡚᭷ᮃどࡉࢀࡿ TiOx/SiOx/⤖ᬗ Si ᵓ㐀ࢹࣂ࢖ࢫࢆ
ᑐ㇟࡜ࡋࠊࡑࡢ㟁Ẽఏᑟ≉ᛶ࡜ࣂࣥࢻ࢔ࣛ࢖࣓ࣥࢺ࡜ࡢ㛵ಀࢆ㆟ㄽࡍࡿࠋ࣮࣮࢟࣡ࢻ㸸 ⤖ᬗ Si ኴ㝧㟁ụࠊࢳࢱࣥ㓟໬≀ࠊ⏺㠃ࠊ໬Ꮫ⤖ྜ≧ែࠊࣂࣥࢻ࢔ࣛ࢖࣓ࣥࢺࠊ
HAXPES⫼ᬒ࡜◊✲┠ⓗ㸸 ⌧ᅾࠊ࠸ࢃࡺࡿ HIT ᆺኴ㝧㟁ụ[1]࡟⥆ࡃ㧗ຠ⋡࣭పࢥࢫࢺࡢ࣊ࢸࣟ᥋ྜᆺ⤖ᬗ Si ኴ㝧㟁ụ࡜ࡋ࡚ࠊࢻ࣮ࣉ࢔ࣔࣝࣇ࢓ࢫ Si ࡢ௦ࢃࡾ࡟㑄⛣㔠ᒓ㓟໬≀㸦TMO㸧ࢆ⏝࠸ࡓ࢟ࣕࣜ࢔㑅ᢥࢥࣥࢱࢡࢺ
㸦CSC㸧ᆺࡢኴ㝧㟁ụࡢ◊✲㛤Ⓨࡀ㐍ࡵࡽࢀ࡚࠸ࡿࠋCSC ᮦᩱࡢ㑅ᢥᣦᶆ࡜ࡋ࡚ࡣࠊ௙஦㛵ᩘࠊ࢟ࣕࣜ࢔⃰ᗘࠊࣂࣥࢻࢠࣕࢵࣉ࡞࡝ࡢ༢యⷧ⭷࡜ࡋ࡚ࡢ≀ᛶ್ࠊࡲࡓࠊSi ࡜᥋ゐࡉࡏࡓᵓ㐀࡟࠾ࡅࡿ㐺ษ࡞ࣂࣥࢻ࢜ࣇࢭࢵࢺࡀᣲࡆࡽࢀࡿࠋࡇࢀࡽኴ㝧㟁ụࢹࣂ࢖ࢫࡢࣂࣥࢻ࢔ࣛ࢖࣓ࣥࢺࢆỴࡵࡿࣃ࣓ࣛࢱ࡟ຍ࠼ࠊSi ⾲㠃ࡢࣃࢵࢩ࣮࣋ࢩࣙࣥ⬟ຊࡢ᭷↓࡟ࡼࡾࠊኴ㝧㟁ụࢹࣂ࢖ࢫ≉ᛶࡀỴࡲࡿࠋࡋࡓࡀࡗ࡚ࠊࡇࢀࡽࢹࣂ࢖ࢫࣃ࣓ࣛࢱࡢᢳฟ࡜ࡑࡢ࣓࢝ࢽࢬ࣒ࡢ⌮ゎࡀ㔜せ࡛࠶ࡿࠋ ࢳࢱࣥ㓟໬≀㸦TiOx㸧ࡣࠊ㟁Ꮚ㑅ᢥࢥࣥࢱࢡࢺᮦᩱ࡜ࡋ࡚᭷ᮃど[2]ࡉࢀ࡚࠸ࡿࡀࠊ⏘ᴗᛂ⏝ࡲ࡛࡟ࡣㄢ㢟ࡀᒣ✚ࡋ࡚࠸ࡿࠋ୺࡞ၥ㢟ࡣࠊTiOx ࡀ♧ࡍ」㞧࡞≀ᛶ࡟⏤᮶ࡍࡿࠋ࣑ࢡࣟ࡞ᵓ㐀ࡸ⤌ᡂࠊࡍ࡞ࢃࡕࠊ໬Ꮫ⤖ྜ≧ែࡢほⅬ࠿ࡽࡢ⌮ゎࡀᚲせࡔࡀࠊ⌧ᅾࡣࡶࡗࡥࡽ᭱⤊ⓗ࡞ࢹࣂ࢖ࢫ≉ᛶࡢ⌧㇟ㄽࡢ⌮ゎ࡟␃ࡲࡗ࡚࠸ࡿࠋᑡ࡞ࡃ࡜ࡶୗグㄢ㢟ࡀᣲࡆࡽࢀࡿࠋ ձࣃࢵࢩ࣮࣋ࢩࣙࣥᛶࢆⓎ⌧ࠊ࠶ࡿ࠸ࡣࠊྥୖࡉࡏࡿࣉࣟࢭࢫࡢ㛤Ⓨ࡜ࡑࡢ࣓࢝ࢽࢬ࣒ࡢゎ᫂ ղ㟁Ꮚ࡟ᑐࡍࡿ࢟ࣕࣜ࢔㍺㏦≉ᛶࢆᨭ㓄ࡍࡿࣂࣥࢻ࢔ࣛ࢖࣓ࣥࢺࡢỴᐃ ճኴ㝧㟁ụࡢᐇືస㸦ග↷ᑕୗ㸧࡛ୖグࣃࢵࢩ࣮࣋ࢩࣙࣥᛶࡸ㟁Ẽ≉ᛶࡀຎ໬ࡍࡿཎᅉࡢゎ᫂ ձࡣࠊTiOx/Si ⏺㠃࡟ Ti-O-Si ⤖ྜᙧᡂࡀࣃࢵࢩ࣮࣋ࢩࣙࣥᛶⓎ⌧࡟ᚲせ࡜ࡢㄝࡀ᭷ຊ࡛࠶ࡿࠋ
ࡓࡔࡋᐇ㝿࡟ࡣࠊTiOx ࠿ࡽ Si ࡢ㛫࡟㑄⛣㓟໬⭷ᒙࡀᙧᡂࡉࢀ࡚࠾ࡾࠊ஧ḟ㞄᥋ཎᏊࡲ࡛ྵࡵࡓ⤖ྜศᕸࢆ⪃៖ࡋ࡚㆟ㄽࡍࡿᚲせࡀ࠶ࡿࠋ ղ࡟㛵ࡋ࡚ࠊᡃࠎࡣࡇࢀࡲ࡛ TiOx/cSi ᵓ㐀ࢥࣥࢱࢡࢺࢹࣂ࢖ࢫ࡟࠾ࡅࡿࣂࣥࢻ࢜ࣇࢭࢵࢺࢆᐇ
㦂ᐊ⣔ XPS ࡛ồࡵࡓ[3]ࠋࡓࡔࡋࠊAr ࢖࢜ࣥࢫࣃࢵࢱ࡜ే⏝ࡋ࡚࠾ࡾࠊ㑏ඖస⏝ࡢ࡯࠿ࠊᚋ㏙ࡍࡿࡼ࠺࡟ࣀࢵࢡ࢜ࣥࡸ࣑࢟ࢩࣥࢢࡢᙳ㡪ࢆࡲࡠ࠿ࢀ࡞࠸ࠋࡇࡇ࡟ࠊ㏆ᖺὀ┠ࡉࢀࡿ᳨ฟ῝ࡉࡢ኱ࡁ࡞◳ X ⥺ග㟁Ꮚศග㸦HAXPES㸧࡟ࡼࡿ᳨ウ[4]ࡀᮇᚅࡉࢀࡿࠋ ᮏ◊✲ㄢ㢟࡛ࡣࠊୖグձ࡜ղ࡟ὀ┠ࡋࠊTiOx ᆺ㟁Ꮚࢥࣥࢱࢡࢺᵓ㐀୰ࡢᇙࡶࢀࡓ⏺㠃࡟࠾ࡅࡿ໬Ꮫ⤖ྜ≧ែࢆ᫂ࡽ࠿࡟ࡋࠊࣂࣥࢻ࢔ࣛ࢖࣓ࣥࢺࡢỴᐃࡸࠊኴ㝧㟁ụᵓ㐀ࢹࣂ࢖ࢫࡢ㟁Ẽ≉ᛶホ౯⤖ᯝ࡜ࡢ┦㛵ࢆ᫂ࡽ࠿࡟ࡍࡿࡇ࡜ࢆ┠ⓗ࡜ࡍࡿࠋ䠉㻝㻜㻠䠉ᐇ㦂㸸 ⤖ᬗ Si ⾲㠃࡟ n++ᣑᩓᒙࢆᙧᡂࡉࡏࡓ TiOx/SiOx/n++Si ᵓ㐀ヨᩱࢆస〇ࡋࡓࠋẚ㍑࡜ࡋ࡚ᣑᩓᒙ
ࡢ࡞࠸ TiOx/SiOx/Si ヨᩱࡶస〇ࡋࡓࠋᇶᯈ࡟ࡣ n ᆺ Si䠄100䠅ࢆ⏝࠸ࠊࡑࡢ⾲㠃࡟ POCl ᣑᩓ࡟ࡼࡾࣜࣥ㸦P㸧ࢻ࣮ࣉࡢ n++ᣑᩓᒙᙧᡂࢆᙧᡂࡉࡏࡓࠋࡑࡢᚋࠊ⇕ H2O2 ⁐ᾮᾐₕ࡟ࡼࡾ⣙ 1.2 nm ཌࡢᴟⷧࢺࣥࢿࣝ㓟໬⭷ࢆᙧᡂࡉࡏࡓࠋࡇࡢ⾲㠃ୖ࡟⣙ 3.5 nm ཌࡢ TiOx ⭷ࢆ⇕ཎᏊᒙሁ✚㸦ALD㸧ἲ࡛ሁ✚ࡉࡏࡓࠋTiOx ሁ✚ᚋࠊࣇ࢛࣮࣑ࣥࢢ࢞ࢫ㞺ᅖẼ࡛ 350°Cࠊ3 min ⇕ฎ⌮ࡋࡓࠋ ࡇࢀࡽヨᩱࢆᑐ㇟࡜ࡋ࡚ HAXPES ࡟ࡼࡿ໬Ꮫ⤖ྜ≧ែࡢ ᐃࢆ SPring-8 ࡢࣅ࣮࣒ࣛ࢖ࣥBL46XU ࡟࡚⾜ࡗࡓࠋບ㉳ X ⥺ࡣ࢔ࣥࢪ࣮ࣗࣞࢱ࠿ࡽⓎ⏕ࡍࡿ⣧ⓑⰍගࢆࢩࣜࢥࣥ஧⤖ᬗศගჾ
䠄111䠅㠃࡜ࡑࡢୗὶ࡟఩⨨ࡍࡿࢩࣜࢥࣥࢳࣕࣥࢿࣝ࢝ࢵࢺỈᬗ䠄444䠅㠃࡟ࡼࡾ༢Ⰽ໬ࡋࡓࡶࡢࢆ⏝࠸ࡓࠋX ⥺࢚ࢿࣝࢠ࣮ࡣ 7939 eV ࡛࠶ࡗࡓࠋບ㉳ගࡢධᑕゅᗘ㸦ヨᩱ⾲㠃࠿ࡽ ᐃࡋࡓゅᗘ㸧ࡣ10°࡛࠶ࡗࡓࠋග㟁Ꮚ࢔ࢼࣛ࢖ࢨ࣮࡟ࡣ VG-Scienta4000 ࢆ⏝࠸ࠊࣃࢫ࢚ࢿࣝࢠ࣮ࡣ 200 eVࠊࢫࣜࢵࢺࢧ࢖ࢬࡣ cueved 0.5 mm ࡛࠶ࡗࡓࠋග㟁Ꮚ⬺ฟゅᗘ㸦take-off angle㸹TOA㸧ࢆ 80oࠊ15o ࡜ࡋࠊ
Si 1sࠊO 1sࠊTi 3d ࡢࢥ࢔ࢫ࣌ࢡࢺࣝࢆ ᐃࡋࡓࠋ୰࿴㖠ࡣ౑⏝ࡋ࡞࠿ࡗࡓࠋ⤖ᯝ࠾ࡼࡧ⪃ᐹ㸸 Si ⾲㠃࡟࠾ࡅࡿ n++ᣑᩓᒙࡢ᭷↓࡟ࡼࡾࠊSi 1s ࡟࠾ࡅࡿᇶᯈ࡜㓟໬≀ࠊࡑࢀࡒࢀࢆ⏤᮶࡜ࡍࡿࣆ࣮ࢡ࢚ࢿࣝࢠ࣮ࡢᕪ㸦¨BE㸧࡟㐪࠸ࡀぢࡽࢀࡓࠋᅗ 1 ࡟ TOA ࡀࡑࢀࡒࢀ(a) 15°ࠊ࠾ࡼࡧࠊ(b) 80°
ࡢሙྜࡢ Si 1s ࢥ࢔ࢫ࣌ࢡࢺࣝࢆ♧ࡍࠋTOA ࡟౫ࡽࡎࠊn++ᣑᩓᒙ࠶ࡾࡢヨᩱ࡟࠾ࡅࡿ'BE ࡀᣑᩓᒙ࡞ࡋࡢሙྜࡼࡾࡶ⣙ 0.4 eV ኱ࡁ࠸ࠋࡇࡢ¨BE ࡢቑຍࡣࠊSiO2 ᒙࡢ SiO2/n++-Si ⏺㠃㏆ഐ࡟ P ࡀከ㔞࡟ࢻ࣮ࣉࡉࢀ࡚࠸ࡿ࠿ࠊࡶࡋࡃࡣࠊṇ࡟ᖏ㟁ࡋ࡚࠸ࡿ࠿ࠊ࠶ࡿ࠸ࡣࡑࡢ୧᪉ࡢຠᯝࡀ⌧ࢀ࡚࠸ࡿࡇ࡜ࢆ♧၀ࡍࡿࠋࡍ࡞ࢃࡕࠊࣂࣥࢻᅗ࡜ࡋ࡚ࡣࠊSi ᇶᯈഃ࠿ࡽ SiO2/n++-Si ⏺㠃࡟㏆௜ࡃ࡟ࡋࡓ
ࡀ࠸ࠊ⾲㠃ࣂࣥࢻࡀ୍ᗘୖ࡟ୖࡀࡾࠊࡑࡢᚋୗࡀࡿࠊ࡜࠸࠺ᥥീࡀ♧၀ࡉࢀࡿࠋࡇࡢࡼ࠺࡞」㞧
࡞ࣂࣥࢻᵓ㐀ࡣࠊᐇ㦂ᐊ⣔ࡢ㌾ XPS ࡛ࡢ⤖ᯝ[3]࡛ࡣ᳨ウ࡛ࡁ࡞࠿ࡗࡓࡇ࡜࡛࠶ࡿࠋ

ᅗ 1㸬⾲㠃 n++ᣑᩓᒙࡢ᭷↓࡟ࡼࡿ Si 1s ࢫ࣌ࢡࢺࣝࡢ㐪࠸㸬䠄a䠅TOA = 15°㸪䠄b䠅TOA = 80°㸬 ୖグࡢࣂࣥࢻ࢔ࣛ࢖࣓ࣥࢺࡢᥥീ࠿ࡽࠊn++ᣑᩓ࠶ࡾࡢヨᩱ࡟࠾࠸࡚ࡣࠊSiO2/n++⏺㠃㏆ഐ࡛ࡢ㟁Ꮚ⃰ᗘࡢቑຍࠊࢺࣥࢿࣝ㞀ቨᖜࡢῶᑡࠊ࠶ࡿ࠸ࡣࡲࡓࠊP ࢻ࣮ࣉ࡟ࡼࡿ㞀ቨ㧗ࡉࡢపୗࠊ࡞࡝ࡢຠᯝ࡟ࡼࡾࠊᮏࢥࣥࢱࢡࢺᵓ㐀ࡀ㟁Ꮚ㍺㏦ࢆࡼࡾቑ㐍ࡉࡏࡿࡇ࡜ࡀᮇᚅࡉࢀࡿࠋᐇ㝿ࠊᮏᵓ㐀ヨᩱࡢ㟁ὶ̿㟁ᅽ≉ᛶࡣࠊᣑᩓᒙ࡞ࡋ࡜ẚ㍑ࡋ࡚ࢥࣥࢲࢡࢱࣥࢫࡀ኱ࡁࡃ࡞ࡿ⤖ᯝࢆᚓ࡚࠸ࡿ[3]ࠋཧ⪃ᩥ⊩㸸
[1] M. Taguchi, M. Tanaka, T. Matsuyama, T. Matsuoka, S. Tsuda, S. Nakano, Y. Kishi, and Y. Kuwano,
Tech. Dig. of the International PVSEC-5, Kyoto, Japan, pp. 689-692,䠄1990䠅.
[2] V. Titova, and J. Schmid, AIP Adv. 8, 125023䠄2018䠅.
[3] H. Lee, T. Kamioka, N. Usami, and Y. Ohshita, MRS Advances 4, 769䠄2019䠅.
[4] T. Nishihara, T. Kamioka, H. Kanai, Y. Ohshita, S. Yasuno, I. Hirosawa, and A. Ogura, ECS J. Solid State
Sci. Technol. 8, Q101䠄2019䠅.

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