Computing apparatus comprising a programmable resistor

• US 4,782,460 A
• Filed: 04/06/1987
• Issued: 11/01/1988
• Est. Priority Date: 04/06/1987
• Status: Expired due to Fees

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.), Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Spencer, Edward G.
• Primary Examiner(s): RUGGIERO, JOSEPH F
• Application Number:
  US07/035,416
• Time in Patent Office: 575 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 364/807, 364/800, 364/801, 364/803, 364/513, 307/201, 382/14, 382/15, 252/500, 330/84, 330/86, 365/100, 365/148, 365/189, 365/218
• US Class Current: 706/39
• CPC Class Codes: G06N 3/063 using electronic means

Abstract

Computing apparatus (e.g., a neural network) advantageously comprises a programmable resistor body comprising typically a multiplicity of resistors R_ij. The resistance of any given R_ij is changeable from a relatively high resistance to a lower resistance by application of an appropriate electrical signal, and can be reset to a higher resistance by application of an appropriate signal of reverse polarity. Exemplarily, a programmable resistor body comprises a thin layer of bismuth oxide or strontium barium niobate.

Claims

1. Electronic computing apparatus comprising

(a) a multiplicity of amplifier means, each one of the amplifier means having at least one input terminal and at least one output terminal;

(b) means for electrically connecting the output terminal of any given amplifier means A_j to the input terminal of at least one other amplifier means A_i, the electrical connection having a predetermined resistance;

(c) means for applying an electrical signal at least to the input terminal of one of the amplifier means; and

(d) means that are responsive to the output signal of at least one of the amplifier means;

characterized in that

(e) the means of (b) comprise a programmable resistor body consisting substantially of a material having a state of relatively high resistivity and having a first and second major surface, a portion S_i of the first surface being associated with A_i and a portion S_j of the second surface being associated with A_j, associated with the programmable resistor body is a resistance R_ij between S_i and S_j, the value of R_ij being changeable from a relatively high value associated with the state of relatively high resistivity to a lower value by application of a "write" voltage between S_i and S_j, and the value of R_ij being furthermore changeable from the lower value to a higher value by application of an "erase" voltage between S_i and S_j ; and

(f) the apparatus further comprises means for applying the "write" voltage and the "erase" voltage between S_i and S_j, such that a predetermined resistance R_ij can be formed between S_i and S_j, and such that the electrical connection of predetermined resistance between the input terminal of A_i and the output terminal of A_j is established.

2. Apparatus of claim 1, wherein the programmable resistor body is a relatively thin layer and wherein at least one of the first and second major surfaces is an interface between the layer and a layer-supporting substrate.

3. Apparatus of claim 1, wherein the material in the relatively high resistivity state has a resistivity that is greater than about 10⁵ Ω

-cm at room temperature.

4. Apparatus of claim 3, wherein at room temperature the maximum value of R_ij is greater than about 10¹⁰ Ω

.

5. Apparatus of claim 1, wherein application of the "write" voltage comprises application of one or more voltage pulses of a given polarity, and wherein application of the "erase" voltage comprises application of one or more voltage pulses of polarity opposite to the given polarity.

6. Apparatus of claim 1, wherein the output terminal of substantially any given amplifier means A_j is electrically connected to the input terminals of a multiplicity of amplifier means, with the given amplifier means A_j optionally being a member of the multiplicity of amplifier means.

7. Apparatus of claim 1, wherein the apparatus is a neural network computer.

8. Apparatus of claim 1, wherein the material having a state of relatively high resistivity is selected from the class consisting of materials of nominal composition Bi₂ O₃, Bi₁₂ GeO₂₀, Bi₁₂ SiO₂₀, Bi₄ Ge₃ O₁₂, and Sr_x Ba_1-x Nb₂ O₆ (0.5≦

x≦

0.7).

9. Apparatus of claim 8, wherein the material is slightly oxygen deficient.