Graphene for future VLSI

Transcription

1 Graphene for future VLSI Fellow ARM Research

2 Why did the semiconductor industry get so excited about graphene? 2

3 The problem with planar MOSFETs Gate Source Drain Substrate One-dimensional field leakage 3

4 Feature Size, um Strain Era Technology Node, um Physical Gate Length, um Year of Production Gate length scaling hampered by leakage, Reduces drive current scaling, Make that up with channel strain to increase mobility

5 mobility CMOS strain era Conventional NMOS Conventional PMOS

6 MOSFET Stress, if at macro scale PMOS Stress 1 square inch chip: NMOS Stress

7 Feature Size, um ~16/14nm: We needed better electrostatics FinFET: Scale gate lengths, Reduce leakage Technology Node, um Physical Gate Length, um Year of Production FinFET gate (blue) can exert field from both left and right

8 Gate All-Around Horizontal Nanowire??? 5nm 3nm 8

9 Materials innovation: Graphene Andre Geim Konstantin Novoselov 2004: + = 2010 Nobel Prize 9

10 Graphene FET Best possible field confinement

11 mobility Device Mobility Comparison graphene N and P Conventional NMOS Conventional PMOS

12 Transistor scaling s dirty secret: Parasitics HS Wong, et al., SISPAD

13 Graphene FET BUT: no band gap! 100x mobility Best possible field confinement Low aspect ratio = low parasitic cap

14 No band gap: Not good for VLSI, maybe OK for AMS Feb 2014: IBM sent a text message using graphene transistors

15 Graphene bandgap? No band gap! Edge treatments Doping Yang, et al., GLSVLSI 2010, pp Hunt, et al. Science, June 2013, v340, n6139 Liu, et al., Nature Nanotechnology 8, 2013, pp

16 Graphene timeline: Andre Geim Konstantin Novoselov 2004: + = 2010 Nobel Prize 16

17 ~30 years discovery to product Representative new material timeline: 1984 GMR Effect discovered 1996 Spin Torque Transfer is proposed ] 1996 Motorola begins MRAM research 1998 First Motorola MTJ 1999 Motorola develops 256Kb MRAM Test Chip 2002 Toggle patent granted to Motorola 2004 Motorola separates semiconductor business into Freescale Semiconductor 2006 Industry first MRAM (4Mb) product commercially available 2008 Freescale Semiconductor spins out MRAM business as Everspin Technologies 2010 Everspin qualifies industry first embedded MRAM 2010 Everspin releases 16Mb density 2012 Everspin produces 64Mb ST-MRAM on a 90 nm process 2016 Everspin announces 256Mb ST-MRAM to customers 17

18 Graphene No band gap! has opened the Pandora s box of 2D materials Yang, et al., GLSVLSI 2010, pp Hunt, et al. Science, June 2013, v340, n6139 Liu, et al., Nature Nanotechnology 8, 2013, pp

19 Graphene for future VLSI ^ and other 2-dimensional materials greg.yeric@arm.com Fellow ARM Research

20 MoS 2 FET Molybdenum Disulfide: Actual band gap (1.9V) These have been made and work My favorite, because it s a MoS 2 FET

21 Molybdenum Disulfide (MoS 2 ) in the wild: 21

22 Transistors: How far can they go? Oct

23 1nm gate length transistor: looks like a transistor 23

24 Feature Size, um Technology node and transistor gate length Technology Node, um Physical Gate Length, um Year of Production 24

25 MoS 2 microprocessor

26 Example of the materials revolution: 2D materials Z. Geng et al., 2D Electronics - Opportunities and Limitations ESSDERC 2016 * These are just the raw materials. Then you can dope, give them edge treatments, etc. 26

27 MoS 2 Molybdenum, a metal Sulfur, a chalcogen Cupric Oxide Berzelianite: copper selenide chalco: copper gen: born from: Weissite: Copper Telluride Covellite: Copper Sulfide oxygen, sulfur, selenium, and tellurium

28 MoS 2 Together, a chalcogenide

29 MoS 2 Specifically, a dichalcogenide

30 MoS 2 Most of the interesting metals for semiconductors are transition metals,.partially filled d sub-shell.

31 MoS 2 So you have a TMD: Transition Metal Dichalcogenide (lazy people say MX2) X 2

32 What can we do with more than one 2D layer? 2012 Device Research Conference 32

33 What if you can t make a good transistor? 33

34 Graphene Nanoscale Resistance Model Primary advantages: reduced size effect impact and resistance Graphene (Stanford 2D Model): R rough,edge = 2 nm λ MFP = 30 nm ρ low = Ω-cm [1] ρ mid = Ω-cm [1] Cu (FS-MS Model): R cu = 0.72 ρ cu = Ω-cm AR cu = 2 p cu = 0.8 λ MFP,cu = 39 nm [1] D. Kondo, N. Yokoyama, et al., Sub-10-nm-wide Intercalated Multi-Layer Graphene Interconnects with Low Resistivity, 2014 IEEE International Interconnect Technology Conference/Materials for Advanced Metallization (IITC/MAM) [ -cm] Cu (Foundry) ρ 0 low Graphene (FeCl 3 ) Line width [nm] R = ρl A ρ mid Graphene (MoO 3 )

35 While everyone is talking about 2D transistors AIST IITC /14nm Cu wire ~32nm wide 35

36 What if you can t make a good transistor? Thermal conductivity 2x copper Breakdown current 10x copper Young s modulus 8x copper Electromigration J MAX 1000x copper 36

37 But wait! There s More (than Moore) 37

38 But wait! There s More (than Moore) valleytronics-advancement-law.html 38

39 But wait! There s More (than Moore) 39

40 2D materials manufacturing: rapid progress 40

41 2D materials manufacturing: rapid progress 41

42 42

43 Graphene is not selfish 43

44 Graphene is not selfish uctors/materials/graphene-makes-infinitecopies-of-exotic-semiconductor-wafers 44

45 Why VLSI might not matter to graphene s success 45

46 Other 2D material uses 46

47 Other 2D material uses 47

48 Other 2D material uses ors/materials/twodimensional-materials-goferromagnetic-creating-a-new-scientific-field 48

49 Other 2D material uses 49

50 Other 2D material uses 50

51 Other 2D material uses 51

52 Other 2D material uses 52

53 Other 2D material uses 53

54 Other 2D material uses 54

55 Other 2D material uses 55

56 Other 2D material uses phene-sieve-may-help-solve-the-worldswater-woes 56

57 Why VLSI might not matter to graphene s success Age of articles cited in this section, in days:

58 Summary Graphene: Will it revolutionize VLSI? Probably not. Graphene did open up a Pandora s Box to a new class of materials (and physics). There is a vast amount of research into other materials, including x-genes and TMDs. We may see improved CMOS devices from this research, but there may also be new transistor paradigms that could replace CMOS: Spin, valley. Graphene and 2D materials could improve signal wiring, thermal problems, and even I/O (photonics, plasmonics) Graphene also recently shown to enable low-cost layer transfer Beyond VLSI, graphene and other 2D materials will almost certainly change the world. There is simply too much diverse research showing promise to not assume this. 58

59 fin 59