Nanoscale Self-Assembly A Computational View

1
Nanoscale Self-AssemblyA Computational View

• Philip Kuekes
• Quantum Science Research
• HP Labs

2
Whats Cooking?Everybody likes Recipes
3
Two Challenges for Nanoelectronics

• Invent a new switching device
• Develop a new fabrication process
• Examine Architecture First

4
HPL Teramacmulti-architecture computer

• 106 gates operating at 106 cycle/sec
• 100 times workstation performance
• Largest defect-tolerant computer ever built
• 220,000 (3) defective components

5
Defect Theology

• Original Sin
• Redemption Through Good Works
• Guilt by Association

6
Redundant Testing
PASS
PASS
PASS
FAIL
PASS
FAIL
PASS
PASS
PASS
PASS
7
Defect Tolerance for Free

• CMOS Technology Configuration bit gt20 x wire
  crossing area
• Molecular Technology Configuration bit smaller
  than wire crossing

8
Teramac Crossbar Architecture
9
Rotaxane Molecular Switch -Prof.
Fraser Stoddart, UCLA
C.P. Collier, E.W. Wong et al.
10
Experimental Realization of a Molecular-Tunneling
Switch
Device Molecule Electrodes
11
Moletronics Architecture

• Wires
• Memories
• Logic
• Integrated Circuits

12
Crossbar at 17 nm half-pitch width
Smallest virus 30-42 nm hepatitis B
13
Parallel ErSi2 wires grown by self-assembly 2 nm
width with a nine nanometer separation
14
Logic Array Design
U V W X Y
Z
Y (U AND V) OR (W AND X) Z V C V-
15
RESET SET 1 SET 2 ENABLE RESTORE INVERT
MOLECULAR SWITCH LATCH EXPT DATA
16
Expt Latch works!
Signal restoration Inversion, if desired gt100mV
operating margin
No nanoscale transistor!
J. Appl. Phys. Feb 1, 2005
17
Random Demultiplexer
18
HP crossbar switches circuits
NAND
16 k
1 k
2005
(ITRS 2018)
64
2004
1
2002
19
How does a Molecular Computer Grow Up?

• Conventional Computer Teacher
• Low Bandwidth Link
• Initially Stupid Molecular Student

20
I Get By With A Little HelpFrom My Friends

• Tutors
• Doctors

21
Complexity

• Self Assembly Thermodynamics
• Arbitrary Graphs

22
Tradeoffs

• Cost of doing the chemistry
• Cost of doing the computing

23
The Pure and the Grubby
24
- Expanders- Cayley Graphs- Ramanujan Graphs
The Math
25

26
Today

• Physical Scientists can only do very simple
  self-assembly
• Mathematicians can create interesting complex
  structures with very simple generators

27
The new capability

• Combine the simple physical processes with the
  mathematical constructions
• Nanoscale self-assembled systems with enough
  complexity to do useful computation.

28
The Physics

• Self-Assembled DNA Nanostructures
• Self-Assembled Surface Chemistry
• Viral Self-Assembly
• Molecular Electronic Circuit Assembly
• DNA-linked Nano-particle Structures

29
The MathAdvantages of Simple Construction

• amenable to self-assembly
• short explicit description
• highly-connected
• sparse

30
Physical StructuresNot Just Abstract Graphs

• defect-tolerance
• efficiently embedded in three-dimensional space
• relatively short edge-lengths.

31
Algorithmic Manufacturing

• Local rules
• Global structure

32
Feedback and the Way Forward

• Computer Code
• Biology
• Chemistry, Physics, Materials Science

33
Feedback and the Way Forward

• Computer Code
• Biology
• Chemistry, Physics, Materials Science
• Reaction Diffusion

34
Stealing from Biology
35
DNA and Proteinsversus Cells
Logic Design as Geometry Spatial
Structure Controlled diffusion Compartments as
wires
36
Organelles
37
Garbage Collection
Ubiquitin Apoptosis Mass transport
38
The Best of Both Worlds
Self-assembly Adaptive External
Programming Self-disassembly
39
Tradeoffs

• Cost of doing the chemistry
• Cost of doing the computing