Congruent state changeable optical memory material and device
AssigneeEnergy Conversion Devices, Inc.
InventorsDavid A. Strand, Stanford R. Ovshinsky
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Abstract
A state changeable memory alloy and device employing same. The memory alloy is capable of changing from a first state to a second state in response to the input of energy, such as projected optical beam energy, electrical energy or thermal energy. The alloy has a first detectable characteristic when in the first state and a second detectable characteristic when in the second state. It is further characterized in that the first state comprises a single phase, and the second state comprises either: (1) a single phase having the same composition as the first phase or (2) a plurality of phases which have substantially similar crystallization temperatures and kinetics.
Claims23
A state changeable memory alloy changeable from a first state to a second state in response to the input of energy, said alloy having a first detectable characteristic when in said first state and a second detectable characteristic when in said second state, and said first and second detectable characteristics selected from the group consisting of reflectivity, band gap, electrical resistance, optical absorption, magnetic susceptibility and thermal conductivity;
- said alloy further characterized in that the first state comprises a single phase and said second state comprises either (1) a single phase having the same composition as said first state or (2) a plurality of phases which have substantially similar crystallization temperatures and kinetics.
A congruent state changeable, chalcogenide, optical memory material capable of existing in at least an amorphous state and a crystalline state, said material having a first detectable physical characteristic or properties index when in the crystalline state and a second detectable physical characteristic or properties index when in the amorphous state and being capable of undergoing a congruent state change upon the application of projected beam energy thereto, said material being of the composition:
- Te.sub.a Ge.sub.b Sb.sub.c
- a, b and c being expressed in atomic percentages and selected such that, when said material is in the crystalline state, and it includes a major portion which has the same composition as the material has when in the amorphous state and a minor portion which has the composition:
- Te.sub.d Ge.sub.e Sb.sub.f,
- d, e and f being expressed in atomic percentages
- wherein the differences between a and d, b and e, and c and f, respectively, total no more than 16 atomic percent.
A state changeable memory alloy changeable from a first state to a second state in response to the input of energy, said alloy having a first detectable physical characteristic or properties index when in said first state and a second detectable physical characteristic or properties index when in said second state, said alloy having the general formula Te.sub.50 (GeX).sub.50 wherein X is Sb, Sn or Bi, said alloy further characterized in that the first state comprises a single phase and said second state comprises either (1) a single phase having the same composition as said first state or (2) a plurality of phases which have substantially similar crystallization temperatures and kinetics.
Dependencies are inferred from the claim text.