Digital Etch for InGaSb p-Channel FinFETs with 10-nm Fin Width - - PowerPoint PPT Presentation

▶
digital etch for ingasb p channel finfets with 10 nm fin
SMART_READER_LITE
LIVE PREVIEW

Digital Etch for InGaSb p-Channel FinFETs with 10-nm Fin Width - - PowerPoint PPT Presentation

Aug 21, 2022 424 likes •681 views

Digital Etch for InGaSb p-Channel FinFETs with 10-nm Fin Width Wenjie Lu and Jess A. del Alamo Massachusetts Institute of Technology CSW, May 30, 2018 Sponsors: KIST, SRC, DTRA, Lam Research Acknowledgment: KIST, NRL, Sandia, MTL, SEBL

slide-1
SLIDE 1

Digital Etch for InGaSb p-Channel FinFETs with 10-nm Fin Width

Wenjie Lu and Jesús A. del Alamo

Massachusetts Institute of Technology CSW, May 30, 2018

Sponsors: KIST, SRC, DTRA, Lam Research Acknowledgment: KIST, NRL, Sandia, MTL, SEBL

slide-2
SLIDE 2

Outline

  • Motivation
  • InGaSb Digital Etch
  • InGaSb p‐channel FinFET
  • Off‐state Current
  • Conclusions

2

slide-3
SLIDE 3

Reported Mobility in InGaSb

3

del Alamo, Nature 2011

High electron mobility

slide-4
SLIDE 4

Reported Mobility in InGaSb

4

del Alamo, Nature 2011

High hole mobility & strain effect InGaSb CMOS

slide-5
SLIDE 5

Digital Etch

5

Digital Etch: standard in InGaAs VNW/FinFET process

Ramesh, IEDM 2017 Zhao, IEDM 2017 Kilpi, IEDM 2017 Vardi, IEDM 2017

slide-6
SLIDE 6

Digital Etch in InGaSb

6

Oxidation Oxide Etch Fin etch

O2 plasma O3 H2O2 H2SO4:H2O HCL:H2O

slide-7
SLIDE 7

Key: Water Damages Antimonides

7

Lu, EDL 2017

 Must remove water

Dip in DI water for 2 min

slide-8
SLIDE 8

After RIE 10% HCl:IPA 2 min

8

Alcohol-based Treatment

Lu, EDL 2017

No sidewall damage

slide-9
SLIDE 9

Digital Etch in InGaSb

9

Oxidation Oxide Etch Fin etch

O2 plasma O3 H2O2 HCl:IPA

slide-10
SLIDE 10

O2 Plasma + HCl:IPA

10

InGaSb InAs HSQ AlGaSb 25 nm After RIE 19 nm 3 cycles (r = 1 nm/cycle) 10 nm 16 nm 10 cycles (r = 0.2 nm/cycle)

r (III-Sb) ↓ after 3 cycles r (III-As) > r (III-Sb)

slide-11
SLIDE 11

Oxidation of GaSb

  • In air:

‒Ga2O3, Sb2O3

  • In strong oxidation agents:

‒Ga2O3, Sb2O3 ‒Sb2O5 (insoluble in common aqueous acid/alkali)

11

Liu, JVST B. 2002

Must avoid formation of Sb2O5

slide-12
SLIDE 12

Experiments of InGaSb DE

12

Best results: RT O2 atmosphere + HCl:IPA

RT O2

slide-13
SLIDE 13

RT O2 + HCl:IPA

13

  • Stable etching rate
  • Identical etch rate for InAs and antimonides

25 nm

No DE

9 nm

4 cycles r = 2 nm/cycle

17 nm

2 cycles r = 2 nm/cycle

InGaSb InAs HSQ AlGaSb

slide-14
SLIDE 14

14

InGaSb p-Channel FinFETs

Heterostructure grown by KIST

Fin

InAs/InAsSb

InAlSb

slide-15
SLIDE 15

15

InGaSb p-Channel FinFETs

Lu, IEDM 2017

Minimum Wf = 10 nm

  • 3 Generations

‒G1: No sidewall treatment ‒G2: HCl:IPA treatment ‒G3: HCl:IPA + digital etch

G3 FinFET

slide-16
SLIDE 16

16

Minimum-size Devices

Lu, IEDM 2015 Lu, CSW 2017 Lu, IEDM 2017

  • 0.8
  • 0.4

0.0 50 100 150 200

  • ID (A/m)

VDS (V)

VGS = 0.5 V to -1 V

G1 Wf = 30 nm, Lg = 100 nm

  • 1.0
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.0 50 100 150 200

  • ID (A/m)

VDS (V)

VGS = 1 V to -1 V

G2 Wf = 18 nm, Lg = 20 nm

  • 1.0
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.0 50 100 150 200

  • ID (A/m)

VDS (V)

VGS = 1 V to -1 V

G3 Wf = 10 nm, Lg = 20 nm

slide-17
SLIDE 17

Off-state Current

17

Presence of leakage paths outside the fins

  • G2: Wf = 20 nm, Lg = 100 nm
  • 1.0
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.0 50 100 150 200

2 fins

  • ID (A)

VDS (V)

1 fin

Same total mesa width

Wm

slide-18
SLIDE 18

Off-state Current

18

  • G2: Vgt = 0.6 V, Vds = ‐ 50 mV

InGaSb HSQ AlGaSb

50 100 2 4 6 8 10

  • IDLG/Wm (nA)

Wf (nm)

~Wf

Wm

slide-19
SLIDE 19

Off-state Current

  • G3: Wf = 20 nm, Lg = 1 µm, VDS = ‐50 mV

19

1 DE cycle significantly improves off current More improvement needed

  • 1.0
  • 0.5

0.0 0.5 1.0 10

  • 2

10

  • 1

10 10

1

10

2

1 DE cycle

  • ID (A/m)

VGS (V)

0 DE cycle

slide-20
SLIDE 20

Benchmark

20

gm/Wf = 704 μS/μm at Wf = 10 nm

50 100 150 200 200 400 600 800

ddd ddd

gm/Wf (S/m) Wf (nm) Planar

FinFETs Gen 3 Gen 2 Gen 1

500 1000 1500 2000 2500 10 100 1000

DE

Gen 2 Gen 3 gm/Wf (S/m) Slin (mV/dec) Gen 1

HCl:IPA

Planar

slide-21
SLIDE 21

Conclusion

  • Digital Etch

‒ Alcohol‐based HCl treatment ‒ O2 for oxidation at RT ‒ Compatible to InGaSb and InAs

  • InGaSb p‐Channel FinFETs

‒ Minimum Wf = 10 nm, Lg = 20 nm ‒ HCl:IPA and DE improves Ioff ‒ Record device performance

21

slide-22
SLIDE 22

Off-state Current

  • G3: Wf = 20 nm, Lg = 1 µm, VDS = ‐50 mV

22

  • 1.0
  • 0.5

0.0 0.5 1.0 10

  • 2

10

  • 1

10 10

1

10

2

4 DE cycle 1 DE cycle

ID (A/m) VGS (V)

0 DE cycle

slide-23
SLIDE 23

Off-state Current

23

  • Buffer is damaged after multiple DE cycles
  • Al0.93Ga0.07Sb is too reactive

10 min air exposure

  • 1.0
  • 0.5

0.0 0.5 1.0 10

  • 2

10

  • 1

10 10

1

10

2

4 DE cycle 1 DE cycle

ID (A/m) VGS (V)

0 DE cycle

3 DE cycle

slide-24
SLIDE 24

Off-state Current

24

HCl:IPA  Super-linear dependency on Wf

  • G2: Vgt = 0.6 V, Vds = ‐ 50 mV

20 40 60 80 100 0.0 0.1 0.2

  • ID  Lg (Am)

Wf (nm)

G2 HCl:IPA 1 min

InGaSb HSQ AlGaSb

slide-25
SLIDE 25

Off-state Current

  • G3: Vgt = 0.6 V, Vds = ‐ 50 mV

25

+ 1 DE  More linear dependency on Wf

20 40 60 80 100 0.0 0.1 0.2

G3 HCl:IPA 1 min + 1 DE

  • ID  Lg (Am)

Wf (nm)

G2 HCl:IPA 1 min