Integrated Circuit with a Radiation-Sensitive Thyristor Structure

A chip card, comprising:

• an integrated circuit, comprising:
• a circuit used for storing or processing data;
• a radiation-sensitive thyristor structure configured to conditionally short two power supply terminals of the integrated circuit,
• wherein the thyristor structure is configured to turn on in response to a region of the thyristor structure being irradiated with radiation to which the thyristor structure is sensitive, in order to establish an electrically conductive connection between a first power supply terminal of the power supply terminals of the integrated circuit and a second power supply terminal of the power supply terminals of the integrated circuit;
• and
• wherein the thyristor structure is configured so that a power density of the radiation needed for the turning on of the thyristor structure is lower than a power density of the radiation needed for a change of data of the circuit used for storing or processing data;
• and
• a cryptographic processor with two supply potential terminals, wherein a first one of the supply potential terminals of the cryptographic processor is connected to the first power supply terminal in an electrically conductive manner, and a second one of the supply potential terminals of the cryptographic processor is connected to the second power supply terminal in an electrically conductive manner;
• and
• wherein the chip card is configured to affect a function of the cryptographic processor in response to a turning on of the thyristor structure.

An integrated circuit, comprising:

• a circuit used for storing or processing data;
• a radiation-sensitive thyristor structure configured to conditionally short a supply voltage terminal and a ground terminal of the integrated circuit;
• a control circuit configured to disable or enable a function of the thyristor structure on the basis of an input signal;
• wherein a first junction between an n-doped first semiconductor structure of the thyristor structure and a p-doped second semiconductor structure of the thyristor structure is meander-shaped in a lateral direction of expansion;
• wherein a p-doped first semiconductor region is arranged in the n-doped first semiconductor structure;
• wherein an n-doped second semiconductor region is arranged in the p-doped second semiconductor structure;
• wherein the n-doped second semiconductor region is doped more heavily than the n-doped first semiconductor structure, and the p-doped first semiconductor region is doped more heavily than the p-doped second semiconductor structure;
• wherein the n-doped first semiconductor structure is connected to the supply voltage terminal of the integrated circuit, and the p-doped second semiconductor structure is connected to the ground terminal of the integrated circuit;
• wherein the thyristor structure is configured to turn on if a potential of the n-doped first semiconductor structure is lowered by at barrier voltage of a second junction between the n-doped first semiconductor structure and the p-doped first semiconductor region with respect to a potential of the p-doped first semiconductor region due to radiation to which the thyristor structure is sensitive, or if a potential of the p-doped second semiconductor structure is increased, due to the radiation, by at least a barrier voltage of a third junction between the p-doped second semiconductor structure and the n-doped second semiconductor region with respect to a potential of the n-doped second semiconductor region;
• wherein a power density of the radiation needed for turning on the thyristor is lower than a power density of the radiation needed for a change of data of the circuit used for storing or processing data;
• wherein the control circuit comprises four inverters connected between the supply voltage terminal and the ground terminal;
• wherein an input of a first one of the four inverters is configured to receive the input signal;
• wherein an output of the first inverter is connected to the n-doped second semiconductor region in an electrically conductive manner;
• wherein the n-doped second semiconductor region is connected to an input of a second one of the four inverters via an electrically conductive structure;
• wherein the electrically conductive structure comprises polysilicon strip and passes along a direction of expansion of the first junction between the n-doped first semiconductor structure and the p-doped second semiconductor structure of the thyristor structure;
• wherein an output of the second inverter is connected to the p-doped first semiconductor region in an electrically conductive manner;
• wherein the p-doped first semiconductor region is connected to an input of a third one of the four inverters in an electrically conductive manner;
• wherein an output of the third inverter is connected to an input of a fourth one of the four inverters;
• and
• wherein an output signal of the control circuit is based on an output of the fourth inverter.

A test method for determining the radiation sensitivity of an integrated circuit, the test method comprising:

• providing an integrated circuit with a radiation-sensitive thyristor structure configured to turn on in response to a region of the thyristor structure being irradiated with radiation to which the thyristor structure is sensitive, a circuit used for storing or processing data, and a control circuit for disabling and enabling a function of the thyristor structure;
• disabling the thyristor structure by the control circuit;
• determining a power density of the radiation needed for a change of data of the circuit used for storing or processing data;
• enabling the thyristor structure by the control circuit;
• and
• determining a power density of the radiation needed for turning on the thyristor structure.

A method for protecting from an attack on a security circuit, the method comprising:

• providing a security circuit with a thyristor structure connected to a supply voltage terminal of the security circuit and connected to a ground terminal of the security circuit, and a cryptographic processor connected to the supply voltage terminal of the security circuit and connected to the ground terminal of the security circuit;
• applying an input signal, by the cryptographic processor, to a control circuit configured to provide an output signal, by using a plurality of functional structures of the thyristor structure;
• detecting the output signal by the cryptographic processor;
• and
• evaluating the output signal by the cryptographic processor and altering a behavior of the cryptographic processor in response to whether the output signal corresponds to an expectation or not.