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

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

“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

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

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

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

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

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

Operational Modes of the Ovonic Phase Change Device OVSHINSKY INNOVATION

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

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

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

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

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

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

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

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

OVSHINSKY INNOVATION

OVSHINSKY INNOVATION

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

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