1. The New Information Age
Stanford R. Ovshinsky
Ovshinsky Innovation, LLC
EPCOS 2008
Prague, Czech Republic

2. Stan & Rosa in “Pontocho” Kyoto, July 2008
OVSHINSKY INNOVATION

3. “A theory is more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended its area of applicability”.
Albert Einstein
OVSHINSKY INNOVATION

4. Ovonic Science, Technology and Products
The underlying science, atomic and orbital engineering can be the basis of a new information age.
Controlled Plasticity
Multi-States
Huge Interactive Parallelism
3D Circuits
Circuit in a Nano-Device
Optical Emitters
Lasers
Optical Computing
Photonics
Electrical-Optical Hybrids
Optical Communications
3-Terminal Devices
Multi-state Memories
Cognitive Devices and Processors
Phase Change Semiconductor Memories
Phase Change Optical Storage
Threshold Switch
The electrical devices have all been demonstrated. The optical devices are basically sound, but require commitment to develop
OVSHINSKY INNOVATION

5. Orbital Interaction and Atomic Engineering – Lone Pairs Make It All Possible
Lone pairs are crucial structurally and electronically.
They influence the conformation/configuration of a molecule by exerting strong repulsive forces on the electron pairs in neighboring bonds and on other lone pairs
Lone Pair Orbitals…. Strength of Repulsions
The Strongest … [Lone Pair Lone Pair]
Next…...….... [Lone Pair Bonding Pair]
The Weakest ….. [Bonding Pair Bonding Pair]
Since lone pairs are not tied down into a bonding region by a second nucleus, they can contribute to moderately low energy electronic transitions.
Lone Pair elements (Te and Se) are based upon entirely different physics than conventional silicon. For example, There are 1023/cc lone-pair electrons in GST, compared to 1014 to 1018/cc dopant atoms in silicon
OVSHINSKY INNOVATION

6. Lone pair Appearance in the element
Group N, bonding site N(N<=4), 8-N(N>4)
Group
s-orbital
p-orbital
Group
s-orbital
p-orbital Ⅰ Ⅴ Ⅱ Ⅵ Ⅲ Ⅶ Ⅳ Ⅷ
OVSHINSKY INNOVATION

7. How Does an Ovonic Threshold Switch Work?
First: Understand Lone Pairs
Crystalline silicon semiconductors require low density of states
Amorphous chalcogenides require high density of states – these come from the lone pairs (spin up/spin down)
Use non-rectifying ohmic contacts - injecting but not reacting
Apply a high field across the device
Couples to the lone pair electrons
Simultaneously, the contacts are injecting electrons into the material which flood the holes
The high conductivity state is instantly reached
Ballistic conduction (no scattering) provides the unique high speed
A solid-state plasma is the result, which can provide more than 50 times the current density of a CMOS transistor
The crosslinked, strong bonding material is not affected by the plasma which insures the structural integrity – The filament does not burn out but expands and contracts as the plasma current changes
The device turns off when the applied voltage goes below the holding voltage and injection has stopped
These processes happen in under a picosecond
Key to function is the use of lone pair electrons, so that the structural bonding electrons in these strongly bonded polymeric materials are not involved. This is the reason the device is so very robust.
Note: This is the basis of operation. Other effects, including tunneling and space charges are also involved.
OVSHINSKY INNOVATION

8. The Phase Change Memory Switch is an Ovonic Threshold Switch!
Typical Threshold Switch IV Curve
The amorphous-to-crystalline transformation starts with an Ovonic switching event
Huge numbers of Lone Pair excitations enable structural transformations by virtue of the plasticity effect of the switching energy
Phase change materials have many fewer and weaker crosslinks than materials in threshold switches, permitting a structural phase change to the more ordered crystalline state to occur
Proper thermal design assures reliable transformations
Completely non-volatile
Typical Memory Switch IV Curve
OVSHINSKY INNOVATION

9. Operational Modes of the Ovonic Phase Change Device
OVSHINSKY INNOVATION

10. Incremental Structural Transformations
Both electrical and optical multi-state operation have been demonstrated
Programming energy changed by changing power at constant time
Programming energy changed by changing time at constant power
amorphous
crystalline
amorphous
crystalline
The plasticity provided by flexibility of the weakly crosslinked structure can be utilized as the plasticity critical to neuronal synaptic circuits
OVSHINSKY INNOVATION

11. New Types of Ovonic Chalcogenide Lone-Pair Devices Can Be Made
Our principles of atomic engineering provide the properties that are key to new kinds of applications.
The following properties have all been demonstrated:
Extremely fast switching
Stable
High dynamic range
Plasticity
Reversible or accumulative
Enables new processing algorithms
Cognitive computing
Respond to both electrical and optical excitation
Including hybrids!
Large change in optical properties
Refractive Index, absorption, non-linear properties
OVSHINSKY INNOVATION

12. An Expanding Family of Devices
Ovonic Semiconductor Switching Devices
Phase Change Memory
Non-volatile, fast, long life, low voltage, low energy, plasticity
Multi-State Phase Change Memory
Higher storage density, plasticity
Threshold Switch
Extremely fast, long life, bipolar
Three-Terminal Threshold Switch
Increased versatility, latching and non-latching
Quantum Control Device
Circuit in a device, multiple space-charge interactions
Cognitive Device
Plasticity, stores and calculates, neuronal and synaptic functions
OVSHINSKY INNOVATION

13. New Phase Change Memory Ovonic Cognitive Function
PCRAM(OUM): Binary Memory
“1”
Set
Reset
Read R
“0”
Cognitive Function: Processing & Memory
State 1
State 2 R +
Signal 1
Signal 2
(Read)
Reset
OVSHINSKY INNOVATION

14. Cognitive Functionality
Ovonic devices can be used singly and together in circuits to provide a huge range of capabilities
Can adapt some algorithms of quantum devices – ideal for factoring
Addition, subtraction, division, multiplication
Huge parallelism
Weighted interconnections using multi-state phase change storage devices
Search engine
Not just matching, but intelligent searches
Learns as you search
Associative capabilities
Ovonic Single and Multiple cells have the same properties as neurons and biological cells
Output fires when the threshold is reached by summing the inputs
The Ovonic Threshold switch does this instantly, continuously and reversibly
The Ovonic Cognitive Device does this through accumulation of input over time
OVSHINSKY INNOVATION

15. Ovonic Quantum Control Device
We have expanded the Ovonic Threshold Switch to make three terminal control and processing devices
Addition of a third electrode between the conventional two electrodes gives control of the threshold switching voltage.
Quantum effects in the space charge region can be exploited for further functionality
OVSHINSKY INNOVATION

16. First Photonic Devices
Phase Angle Steering
Combining multistate capability with optical structures optimized to emphasize refractive index change while minimizing reflection change gives a device that can reflect at different angles, hence beam steering.
Add/Drop Filter
Use of phase change materials in optical resonator structures allows for tuned/detuned resonant conditions, hence transfer/passing of input signals
OVSHINSKY INNOVATION

17. Fast response: 10’s nanosec MEMS(>milli-sec)
Optical telecomunication beam steering by the phase change mirror film D. V. Tsu, R.O. Miller, D. Strand “All optical broadband steering by Phase Angle Controlled Stationary Element(PACSE) mirrors”: Proc. SPIE
All optical operation: Phase Change by 650nm LD, Signal of NIR (1550nm) LD
Fast response: 10’s nanosec
MEMS(>milli-sec)
Steering angle: >2 degree
OVSHINSKY INNOVATION

18. OVSHINSKY INNOVATION

19. OVSHINSKY INNOVATION

20. Summary
Ovonic switches opened a new field of study, new applications, and new products.
Optical disk storage is mature, yet still evolving.
Electrical phase change memories are nearing the market.
Cognitive devices and computers will follow.
Optical communication devices have been demonstrated.
Electrical/optical hybrids have been demonstrated, many more to follow.
Optical computing? Ovonic atomically engineered chalcogenides are ideally suited.
The needs of the new information age can be fulfilled by the Ovonic approach
OVSHINSKY INNOVATION

21. You can open the door to new stage by your disciplinary
Let’s connect the marvelous metallurgical materials ability of the audience with the electronic and photonic properties which I have explained.
What is the simplicity?
The simplicity can be stated by that a material can be atomically engineered to have a high density of non-bonded lone pairs and thereby have new mechanisms and properties.
How extended is the applicability?
These mechanisms and properties can provide scalable new materials and devices that can replace silicon and be the science and technology of the new information age.
Let’s all become multidisciplinary and therefore multifunctional.
OVSHINSKY INNOVATION