Method and apparatus for capacitorless double-gate storage

1. A method of operating an electronic memory circuit comprising:

attracting charge carriers onto a back interface of a body by applying a voltage to a back gate;

detecting a number of charge carriers at said back interface by measuring a drain current; and

using said measured drain current to determine a value stored on said electronic memory circuit; and,

placing said memory circuit in a hold state by applying a first hold gate voltage to said front gate and a second hold gate voltage to said back gate and applying nearly equal voltages to said source and said drain.

2. A method of operating an electronic memory circuit comprising:

attracting charge carriers onto a back interface of a body by applying a voltage to a back gate;

detecting a number of charge carriers at said back interface by measuring a drain current; and

using said measured drain current to determine a value stored on said electronic memory circuit; and,

periodically performing a purge of excess carriers in a body by applying a first purge gate voltage to said front gate and a second purge voltage to said back gate and applying purge voltages to said source and said drain.

3. A method of operating an electronic memory circuit comprising:

attracting charge carriers onto a back interface of a body by applying a voltage to a back gate;

detecting a number of charge carriers at said back interface by measuring a drain current; and

using said measured drain current to determine a value stored on said electronic memory circuit; and,

a write is performed by a front gate write voltage, a back gate write voltage substantially different from said front gate write voltage, and a drain-source voltage less than or greater than a critical value for impact ionization (˜E gap,Si /q), depending on whether a “O” or “1” is desired to be written;

a hold is performed by a front gate hold voltage different from said front gate write voltage, a back gate hold voltage of about said back gate write voltage, a source hold voltage and a drain hold voltage biased at a same hold voltage;

a read is performed by a front gate read voltage of about said front gate write voltage, a back read gate voltage substantially different from said front gate write voltage, a source read voltage about between said front gate read voltage and said back gate read voltage, and a drain voltage somewhat different from said source read voltage and less than a critical value for impact ionization; and a purge is performed by a front gate purge voltage of about said front gate write voltage, a back gate purge voltage nearer to said front gate purge voltage than said back gate write voltage, a source purge voltage of about said back gate purge voltage or about ground, and a drain voltage about between said source purge voltage and said back gate purge voltage.

4. A method of operating an electronic memory circuit comprising:

attracting charge carriers onto a back interface of a body by applying a voltage to a back gate;

detecting a number of charge carriers at said back interface by measuring a drain current; and

using said measured drain current to determine a value stored on said electronic memory circuit; and,

periodically performing a static purge of said back interface.

5. The method of claim 4 further wherein said static purge is performed by a method comprising:

holding a voltage at said back interface unchanged throughout all operation modes of said memory circuit; during said static purge, changing a front gate voltage to a positive value to reduce a potential barrier between source and body.

6. The method of claim 5 further comprising:

grounding a source voltage to further reduce said a potential barrier between source and body.

7. The method of claim 5 further comprising:

in an array comprising multiple instances of said memory circuit:

keeping one block of said multiple instances of said memory circuit vacant;

copying data from a non-vacant block into said vacant block;

performing a purge on all memory circuits in said non-vacant block which then becomes a vacant block for a next static purge operation.

8. A method of operating an electronic memory circuit comprising:

attracting charge carriers onto a back interface of a body by applying a voltage to a back gate;

detecting a number of charge carriers at said back interface by measuring a drain current; and

using said measured drain current to determine a value stored on said electronic memory circuit;

a back gate voltage is held constant and substantially different from a front gate write voltage;

a write is performed by a front gate write voltage, and a drain-source voltage less than or greater than a critical value for impact ionization (˜E gap,Si /q), depending on whether a “O” or “1” is desired to be written;

a hold is performed by a front gate hold voltage different from said front gate write voltage, a source hold voltage and a drain hold voltage biased between said front gate hold voltage and said back gate voltage;

a read is performed by a front gate read voltage of about said front gate write voltage, a source read voltage between said front gate read voltage and said back voltage, and a drain voltage somewhat different from said source read voltage and less than a critical value for impact ionization; and

a static purge is performed by reducing a potential barrier between source and body regions of said memory cell.

9. A method of operating an electronic memory circuit comprising:

attracting charge carriers onto a back interface of a body by applying a voltage to a back gate;

detecting a number of charge carriers at said back interface by measuring a drain current; and

using said measured drain current to determine a value stored on said electronic memory circuit;

a write is performed by a front gate voltage of about 1 V, a back gate voltage of about −1 V, a source voltage of about 0 V, and a drain voltage of about 0.5 V or 1.2 V depending on the desired write value;

a hold is performed by a front gate voltage of about 0 V, a back gate voltage of about −1 V a source voltage of about 0.5 V, and a drain voltage of about 0.5 V;

a read is performed by a front gate voltage of about 1 V, a back gate voltage of about −1 V, a source voltage of about 0 V, and a drain voltage of about 0.5 V; and

a purge is performed by a front gate voltage of about 1 V, a back gate voltage of about 1 V, a source voltage of about 0 V, and a drain voltage of about 0.5 V.