STJ?????? ????(KEK)

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STJ??????????(KEK)
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STJ Overview

• Superconducting Tunneling Junction Detector
  (????????)
• meV???????photoconductor
• ?????????????????????????????????? ?????????

meV??
????????? ?????? ????????? ??????????
SIS??
3
???????????????
????
?????????(CMB) ???????????
?????????? ?????????
??
meV??????? ?????????
4
???????
??1
??????? ???? (30-300GHz) Al?Nb??? ?????? ??? ?????
?
????????????????????? ????????????
??2
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STJ???????

• Al STJ???(1000ch)???
• Hf STJ???

????????????

• ?????????????????????????? (???????raison
  dêtre)
• ???????(????????)???????????

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????????
?????? ??????? ?????? ?1/10? ????
Al 120mK Hf 16mK
ADR??????
?????
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STJ????????
?Al STJ (??????) ?Hf STJ (???????????) ???
????????
?????????????
???? ????????????? ???? ??? KEK??????? ???
? KEK????????? ??????????????????????
???????????????????? KEK??????????? ?
???????? KEK????????? ????????? JAXA????????
???? ??????? Soo-Bong Kim ???? ?????????
???? ???? ??? ?????? ???????????????
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CMB???????????????

• KEK CMB group
• (QUIETPolarBeaR)
• Formed in Dec. 2007
• Members
• Masashi Hazumi
• Masaya Hasegawa
• Takeo Higuchi
• Osamu Tajima
• Takayuki Tomaru
• Yuji Chinone (D1)

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STJ????????

• Hf STJ?2007?2??Al STJ?2007?5????
• ???????????!???STJ?????????????????????
• ???????????????
• ??????????KEK?????????????KEK??????
• KEK?????????????

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????????(X?????STJ??)
???????????????
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???????
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Buffer Layer(Al2O3) sputtering
Layer material Condition Rate Thickness time
1 Buffer Sputter Al2O3 Ar 50sccm 1.3Pa, 400W 215 A/min 1,000 A 440
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Tri-Base Al sputtering
Layer material Condition Rate Thickness time
2 Tri Sputter Al Ar 50sccm 1.1Pa, 250W 922 A/min 500 A 33
Oxidation AlOx O2 100 sccm 30Torr 23nm/30TH 2030 A 60 (30TH) Torr x Hour
Sputter Al Ar 50sccm 1.1Pa, 250W 922 A/min 500 A 33
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Tri-Middle AlOx
Layer material Condition Rate Thickness time
2 Tri Sputter Al Ar 50sccm 1.1Pa, 250W 922 A/min 500 A 33
Oxidation AlOx O2 100 sccm 30Torr 23nm/30TH 2030 A 60 (30TH) Torr x Hour
Sputter Al Ar 50sccm 1.1Pa, 250W 922 A/min 500 A 33
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Tri-JD Al
Layer material Condition Rate Thickness time
2 Tri Sputter Al Ar 50sccm 1.1Pa, 250W 922 A/min 500 A 33
Oxidation AlOx O2 100 sccm 30Torr 23nm/30TH 2030 A 60 (30TH) Torr x Hour
Sputter Al Ar 50sccm 1.1Pa, 250W 922 A/min 500 A 33
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???
Layer material Condition Rate Thickness time
3 Protection Sputter SiO2 Ar 50sccm 1.3Pa, 400W 554 A/min 240 A 26
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??????
Layer material Condition Rate Thickness time
4 Resist JD RE11 MD5-JD
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??
Layer material Condition Rate Thickness time
4 Resist JD RE11 MD5-JD
19
??
Layer material Condition Rate Thickness time
4 Resist JD RE11 MD5-JD
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JD???????
Layer material Condition Rate Thickness time
5 Junction Etching SiO2 CF4 50sccm 20Pa, 30W 477 A/min 250 A 1
Define (JD) (RIE 1) Al CF4 50sccm 4Pa, 30W 46 A/min 550 A 2x6 (3) ?? 1x12?
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JD???????
Layer material Condition Rate Thickness time
5 Junction Etching SiO2 CF4 50sccm 20Pa, 30W 477 A/min 250 A 1
Define (JD) (RIE 1) Al CF4 50sccm 4Pa, 30W 46 A/min 550 A 2x6 (3) ?? 1x12?
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??????
Layer material Condition Rate Thickness time
6 Edge ?????? O2 O2 30 sccm 13Pa, 30W --- --- 1
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??????
Layer material Condition Rate Thickness time
7 Resist?? ?5/14 1900
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???
Layer material Condition Rate Thickness time
8 Protection Sputter SiO2 Ar 50sccm 1.3Pa, 400W 554 A/min 240 26
25
????????????
Layer material Condition Rate Thickness time
9 Resist BE RE11(???13)MD5-BE ?5/15 1230
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BE pre-etching
Layer material Condition Rate Thickness time
10 BE (Base Etching SiO2 CF4 50sccm 20Pa, 30W 477 A/min 250 A 1
Electrode) (RIE 1) Al CF4 50sccm 4Pa, 30W 46 A/min 550 A 2x6 (3) ?? 1x12?
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BE ??etching
Layer material Condition Rate Thickness time
10 BE (Base Etching SiO2 CF4 50sccm 20Pa, 30W 477 A/min 250 A 1
Electrode) (RIE 1) Al CF4 50sccm 4Pa, 30W 46 A/min 550 A 2x6 (3) ?? 1x12?
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??????
Layer material Condition Rate Thickness time
11 Resist??
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Insulation Layer
Layer material Condition Rate Thickness time
12 Insulation Sputter SiO2 Ar 50sccm 1.3Pa, 400W 554 A/min 1,000 A 148
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Contact Hall (pad???????)
Layer material Condition Rate Thickness time
13 Resist BE RE11 MD5-CH
14 CH Etching SiO2 CF4 50sccm 20Pa, 30W 477 A/min 1,500 A 4 ?5/15 1750
15 Resist?? ?5/15 1830
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Nb wire
Layer material Condition Rate Thickness time
16 Wire Sputter Nb Ar 50sccm 1.1Pa, 330W 878 A/min 3,000 A 142x2 (5) Ar??
17 Resist W RE11 MD5-W ?5/16 1200
18 Wire Etching Nb CF4 50sccm 20Pa, 30W 355 A/min 3,000 A 9 ?5/16 1230
19 Resist??
20 ??resist ??? 5 ?5/16 1300
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X??Al-STJ
S
I
S
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??????Al/Nb-STJ??
????????Nb/Al-STJ???
S
I
S
??????STJ
X??STJ
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Nb/Al-STJ??0.3K???????X???
0.3K?????
X???????
Fe55??
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I-V??SIS??????????????????
R
Vin V IR
B
Vin
V
I
I
I
V
V
2D
??? ???????????? ???????????? ????
??? ????????????? ??????(??????????)
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Nb/Al-STJ???He4????????I-V??
????STJ(100µm)
0.63K
1.6K
1.6K
??10mA/div
??50µA/div
??5nA/div
??????? 5nA_at_200µV 40µA (1.6K)
????
????
??0.2mV/div
??1mV/div
??0.5mV/div
??????STJ(f7µm x 2)
0.63K
1.6K
1.6K
1MO
??1nA/div
??500nA/div
??50µA/div
??????? 0.3nA _at_ 400µV 180nA (1.6K)
????
????
??0.5mV/div
??1mV/div
??2mV/div
???????Nb/Al-STJ?????????? ????????????????????
??0.5mV/div
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Al-STJ???????????
??
Microwave studio
????????
???
???????
????STJ ???
??????? 818mm ?????? 547mm (1/4??) ?????
4.46mm STJ???? 10 mm2
?????????
72GHz????
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??????????
??
?????? ??????
??(?????????)??????????
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??????Al-STJ??
??5µV/div
S
????
I
S
??????STJ(f7µm x 2)

• ????650µV(Al x 2)
• 25nA_at_200µV
• ???????????????
• ?ADR?100mK??
• I-V?????

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Hf-STJsDepo. condition
H.Sato
This was a first time for us to make Hf films.
So, deposition condition should be fixed firstly.
(... And So far, nobody succeed in making Hf-STJs
in the world.)
search condition for stress-free layer

300W, 1.5Pa was good for Hf deposition
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????????
H.Sato
????????(ADR)?Hf?????????????????
???Hf?Tc165mK
300???
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Hf-STJsTc measurement
H.Sato
We tried to realize a same Tc as bulk Hf.
Finally, we found that deposition with substrate
heating at 300 deg. was effective.
Tc was measured by using ADR.
T80mK
Same as Tc of bulk Hf.
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Hf-STJsFabrication
H.Sato
Hf was very hard to dry-etch with our RIE.
We introduced a lift-off method with Al-metal
mask.
We obtained Tc166mK with this fabricated Hf.
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X??Ta/Al-STJ??

• Ta ADR?????????????????
• ???????

S
I
S
Nb??????Ta? ?????????
45
1.7K?IV???????????
17
56
26
35
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9?????????????STJ15??IV??????
33
53
62
71
46
?????STJ???????????
?????????????????
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100GS-3
raw signal
preamp out 1V IB0.166A VB-4.89V
shaper output
Ka
tail?????? ???leakage??
Kß
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• ??????????????????

????Yale???RF-STJ????????????????? IEE Trans.
Appl. Superconductivity Vo.17 p.241
(2007) STJ?????????????????????????
???????? ??? (??????)
?????? STJ
?????????????????!
KEK?????? ????KEK? ??
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KEK??????
50
???????????

• ?????????????
• ??????????????????
• ??300m2??????????
• ?????????????????????????????????????????????????
  ?
• ??????????????????????????????????????????????

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?????????

• JIS??????????????
• ?????????????????
• 3????
• 10m x 15m????(???10?)
• ????OK????????????????????????????
• 10m x 15m????????(???10000?1000)
• ???1000??????????????(6m x 4m)

???
???????
10?????? ??????? ??????
???????
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??(?)
53
???
??(?)

• ????????????(??????????)
• ?????????????????

????????????
???????
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0.3K?????????_at_KEK

• ????????????????????????????

???? 300mK?? 112??25?
0.3K??I-V?????????KEK???????????
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?????_at_???????????
??

• 1990???????Oxford??????(?????????????)???
• ?????????????????????????

Dilution Refrigerator??? 200?W at 100mK

• Pump???????????TMP?????????
• ??
• ????????
• ????????????
• TMP, RP???
• ????
• ???????????
• ?????????

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STJ???
NTT???????2006.6 p.25
?????(??????????????????????)? ???????????? ?
??????????????!
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???

• ??2009?2?20??21?
• ??KEK
• ??????????????????
• STJ?TES??????????????????
• ???RD?????????????????????(????????????etc.)
• ?????(KEK)???(??)??????(?????)???(JAXA)