Engineering Terminology
"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

Cross section (sigma) is the device SEE response to ionizing radiation. For an experimental test for a specific LET, sigma = #errors/(ion fluence). The units for cross section are cm2 per device or per bit.

JAN. Joint Army Navy. Which is a specification and screening process.

LET threshold (LETTH) is the minimum LET to cause an effect. The JEDEC recommended definition is the first effect when the particle fluence = 107 ions/cm2.

Linear Energy Transfer [LET] is a measure of the energy transferred to the device per unit length as an ionizing particle travels through a material. The common unit is MeV-cm2/mg of material (Si for MOS devices).

Post-irradiation Parameter Limits [PIPL].

Radiation failures Is defined at the lowest radiation level when either any device parameter exceeds its specified post irradiation parameter limits (PIPL) or the device fails any functional test in accordance with stated test conditions.

Radiation hardness assurance (RHA) That portion of performance verification testing that assures that parts meet the radiation response characteristics as specified in this specification and the specification sheet. The JAN screening process provides for RHA level designators M, D, P, L, R, F, G and H which are appended to the device prefix to identify devices, which have passed RHA requirements. An example JANHC; JAN screening, RHA; 'H' and Military 'C'.

Safe Operating Area [SOA] Refer to the page covering the 2N3634 Transistor for a graph, or use the links at the top of the page for a definition.

Sensitive volume refers to the device volume affected by SEE-inducing radiation. The geometry of the sensitive volume is not easily known, but some information is gained from test cross section data.

Single Event Burnout [SEB] is a highly localized burnout of the drain-source in power MOSFETs. SEB is a destructive condition.

Single Event Effect [SEE] is the amount of irradiation a device can handle.

Single Event Functional Interrupt [SEFI] is a condition where the device stops operating in its normal mode, and usually requires a power reset or other special sequence to resume normal operations. It is a special case of SEU changing an internal control signal. One example would be a DRAM entering the test mode defined by JTAG [IEEE 1149.1].

Single Event Latchup [SEL] is a potentially destructive condition involving parasitic circuit elements forming a silicon controlled rectifier [SCR]. In traditional SEL, the device current may destroy the device if not current limited and removed "in time."  A "microlatch" is a subset of SEL where the device current remains below the maximum specified for the device. A removal of power to the device is required in all non-catastrophic SEL conditions in order to recover device operations.

Single Event Gate Rupture [SEGR] is the burnout of a gate insulator in a power MOSFET. SEGR is a destructive condition.

Single Event Upset [SEU] is a change of state or transient induced by an ionizing particle such as a cosmic ray or proton in a device. This may occur in digital, analog, and optical components or may have effects in surrounding circuitry. These are "soft" bit errors in that a reset or rewriting of the device causes normal behavior thereafter. A full SEU analysis considers the system effects of an upset. For example, a single bit flip, while not damaging to the circuitry involved, may damage the subsystem or system (i.e., initiating a pyrotechnic event).

Single Hard Error [SHE] is an SEU which causes a permanent change to the operation of a device. An example is a permanent stuck bit in a memory device.

Radiation Sign
Radiation Symbol

Editor Note; this page of definitions of terms was developed by and from the US government. However the text has been modified over time, including having links added. The government source is unknown.

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