Neutron detector cell efficiency
Neutron detection cells and corresponding methods of detecting charged particles that make efficient use of silicon area are set forth. Three types of circuit cells/arrays are described: state latching circuits, glitch generating cells, and charge loss circuits. An array of these cells, used in conjunction with a neutron conversion film, increases the area that is sensitive to a strike by a charged particle over that of an array of SRAM cells. The result is a neutron detection cell that uses less power, costs less, and is more suitable for mass production.
1. A charged particle detector comprising:
first and second voltage sources;
a signal node;
one and only one bitline for reading and writing signals to the charged particle detector;
a first transistor coupled between the first voltage source and the bitline, the first transistor having a gate terminal coupled to the signal node;
a second transistor coupled between the second voltage source and the signal node; and
a circuit element coupled between the first voltage source and the signal node, wherein the circuit element comprises a third transistor, the third transistor having a gate terminal coupled to a third voltage source, and
whereby charged particles incident upon the second transistor create a conduction path between the second voltage source and the signal node and temporarily apply a voltage of the second voltage source to the signal node.
2. The charged particle detector of claim 1 , wherein the second transistor has a floating body.
3. The charged particle detector of claim 1 , further comprising a charge collector coupled between the second voltage source and the signal node, wherein the charge collector is selected from the group consisting of a diode, a BJT, and a MOSFET.
4. The charged particle detector of claim 1 , wherein the signal node is a first signal node, and wherein the second transistor has a gate terminal coupled to a second signal node, and wherein the charged particle detector further comprises:
a third transistor coupled to the first transistor forming an inverter, the inverter coupled between the first and second voltage sources, and the inverter having an input coupled to the first signal node and an output coupled to the second signal node;
a fourth transistor coupled between the bitline and the first transistor, the fourth transistor having a gate terminal coupled to a wordline.
5. A method of detecting the presence of charged particles, the method comprising:
providing a latch, the latch comprising one and only one bitline, first and second voltage sources, first and second signal nodes, and first and second inverters, each inverter comprising a pFET and an nFET, wherein each inverter is coupled between the first and second voltage sources,
wherein the first signal node is coupled between an input of the first inverter and an output of the second inverter, wherein the second signal node is coupled between an input of the second inverter and an output of the first inverter, wherein the first signal node has a voltage that is generally equal to a voltage of the first voltage source, and wherein the second signal node has a voltage that is generally equal to a voltage of the second voltage source;
multiplying a charge deposited by the charged particles by floating a body of at least one of the pFET and nFET that comprise the second inverter;
coupling a charge collector between the first signal node and the second voltage source, wherein the charge collector is selected from the group consisting of a diode, a BJT, and a MOSFET, and whereby charged particles incident upon the charge collector create a conduction path between the first signal node and the second voltage source and act to upset the latch; and
reading the voltage of the second signal node onto the bitline, the voltage indicating whether an upset has occurred.
6. A method of detecting the presence of charged particles, the method comprising:
providing a charged particle detector, the charged particle detector comprising
a first transistor coupled between a first voltage source and a bitline, the first transistor having a gate terminal coupled to a signal node;
a circuit element coupled between the first voltage source and the signal node, the circuit element including a conduction path between the first voltage source and the signal node, wherein the circuit element is selected from the group consisting of a resistor and a transistor having a gate terminal coupled to a Vbias line;
a second transistor coupled between a second voltage source and the signal node, whereby charged particles incident upon the second transistor create a conduction path between the second voltage source and the signal node and temporarily apply a voltage of the second voltage source to the signal node, and whereby the voltage of the second voltage source appearing on the signal node acts to temporarily apply a voltage of the first voltage source to the bitline; and
monitoring a voltage on the bitline, whereby the presence of charged particles is indicated by a temporary voltage appearing on the bitline that is substantially equal to the voltage of the first voltage source.
7. The method of claim 6 , wherein the charged particle detector further comprises a charge collector coupled between the signal node and the second voltage source, wherein the charge collector is selected from the group consisting of a diode, a BJT, and a MOSFET, and whereby charged particles incident upon the charge collector create a conduction path between the second voltage source and the signal node and temporarily apply the voltage of the second voltage source to the signal node.
8. A charged particle detector comprising:
first and second voltage sources;
a signal node;
one and only one bitline for reading and writing signals to the charged particle detector;
a first transistor coupled between the first voltage source and the bitline, the first transistor having a gate terminal coupled to the signal node;
a second transistor coupled between the second voltage source and the signal node; and
a circuit element coupled between the first voltage source and the signal node, wherein the circuit element comprises a resistor.
9. The charged particle detector of claim 8 , wherein the resistor has a resistance value of not less than 100 kΩ.
10. The charged particle detector of claim 8 , further comprising a charge collector coupled between the second voltage source and the signal node, wherein the charge collector is selected from the group consisting of a diode, a BJT, and a MOSFET.
11. The charged particle detector of claim 8 , wherein the second transistor has a floating body.
12. The charged particle detector of claim 8 , wherein the signal node is a first signal node, and wherein the second transistor has a gate terminal coupled to a second signal node, and wherein the charged particle detector further comprises:
a third transistor coupled to the first transistor forming an inverter, the inverter coupled between the first and second voltage sources, and the inverter having an input coupled to the first signal node and an output coupled to the second signal node;
a fourth transistor coupled between the bitline and the first transistor, the fourth transistor having a gate terminal coupled to a wordline.
13. A charged particle detector comprising:
first and second voltage sources;
a signal node;
one and only one bitline for reading and writing signals to the charged particle detector;
a first transistor coupled between the first voltage source and the bitline, the first transistor having a gate terminal coupled to the signal node;
a second transistor coupled between the second voltage source and the signal node; and
a third transistor coupled between the first voltage source and the signal node, wherein the third transistor comprises a weakened pFET or a weakened nFET.
14. The charged particle detector of claim 13 , wherein the second transistor has a floating body.
15. The charged particle detector of claim 13 , further comprising a charge collector coupled between the second voltage source and the first signal node, wherein the charge collector is selected from the group consisting of a diode, a BJT, and a MOSFET.
16. The charged particle detector of claim 13 , wherein the signal node is a first signal node, wherein the second transistor has a gate terminal coupled to a second signal node, wherein the third transistor has a gate terminal coupled to the second signal node, and wherein the charged particle detector further comprises:
a fourth transistor coupled to the first transistor forming an inverter, the inverter coupled between the first and second voltage sources, and the inverter having an input coupled to the first signal node and an output coupled to the second signal node; and
a fifth transistor coupled between the bitline and the first transistor, the fifth transistor having a gate terminal coupled to a wordline.