pulsed laser irradiation for discrete component

Increased desktop computer power and the advancement of simulation tools enable accurate modeling of the radiation effects of different environments. “Best guess” dose rate models have been created for individual components based on the physical characteristics of the device with good accuracy [1-3]. The variable with this technique is the metallization coverage of the active area of ​​the mold.

In order to determine the suitability of electronics for the environment, the behavior of the electronics in the dose rate environment must be defined. As can be seen from Equation 2.1, the photocurrent generated varies with the dimensions of the collection and excitation regions applied to the junction. In practice, instead of inserting discrete values ​​for Ipp based on specific values ​​of the dose rate, which is the photocurrent generation parameter, Kpp was determined as the slope of Ipp vs.

According to Figure 2-2, the slope of the lines for each of these devices would be the Kpp value. However, this value varies for each type of device and depends mainly on the geometry of the specific device. This phenomenon is due to the internal collapse of the junction depletion region and intrinsic resistive effects and is therefore not considered in this study.

The CT-2 probe measures the current through the collector of the DUT and is terminated with 50 Ohms. The automated data displays other information such as total ionizing dose effects and peak-to-peak measurements for each of the stored transients. The dynamic range of the laser facility is significantly greater than the range used in this study.

Based on these data and the capabilities of the laser apparatus, dose rates lower than 109 rad(Si)⋅sec-1 and greater than 1012 rad(Si)⋅sec-1 are readily available, if desired. The modeling technique described in this project projects the linear part of Ipp against a practical illustration of different CFs comes from comparing the data sets in Figures 4-4 (a and b).

Since LINAC provides events that are closest to those in the weapons environment, LINAC should. However, the noise associated with LINAC data calls into question the true validity of LINAC-derived Kpp values. To apply this technique to an unknown part, the device geometry family and die metal coverage must first be determined.

This CF can be applied directly to the slope value extracted from the Ipp laser data or to the Ipp vs.

Figure 2-1: Dose-rate effects on an unbiased P-N junction. (a) High energy radiation generates majority carriers in the conduction and valence bands producing a current flow opposite the normal operation of the device

Use Percent-Covered Number to find Conversion Factor (CF) on

Use Die Photo to Perform

The use of a pulsed laser to acquire dose rate data provides an inexpensive bench-top alternative to the LINAC device. A very reliable laser can be purchased commercially and a test setup to perform this testing to obtain modeling information can be set up in almost any laboratory. The laser approach provides high signal-to-noise data with signals that can be easily simulated in a SPICE-like environment for model validation.

It has also been suggested that for small integrated circuits (ICs) a pulsed laser could be used to verify macromodels. These applications are generally tailored specifically for each type of device and are calibrated with LINAC data, providing little flexibility to the process. The linear relationship between percent metal coverage and conversion factor provides a very good estimate of the equivalent dose rate and provides a very reasonable alternative to LINAC testing.

Limiting the application to modeling purposes leaves device evaluation testing (DET) and qualification testing to be performed at a LINAC facility without disruption to model development. This is not a suggestion that dose rate laser testing can completely replace LINAC or flash X-ray testing, but there are real advantages for the specific application of model development and evaluation: the laser data can be repeated with a known pulse shape over a large dynamic range without long-term radiation damage to the tested units. The primary outcome of this research is to establish a way to correlate laser pulse energy results to an equivalent dose rate value without having to use a LINAC to validate the data.

It has been demonstrated that laser dose rate data can be converted to equivalent LINAC data and that percent metallization coverage is linearly related to the conversion factor of individual devices based on device geometry. By determining the device geometry family and using the percent metal coverage of the die active surface, an appropriate conversion factor can be determined from an image showing this relationship and can be applied to the laser data to determine the dose rate or applied directly to the slope of the laser data to determine the correlation Kpp for insertion into dose rate models. This process can be performed with a conventional laser and can be quickly used to create models for ever-changing lists of separate parts for weapons systems development.

Habing, “Using lasers to simulate radiation-induced transients in semiconductor devices and circuits,” IEEE Trans. Kim, “Using a pulsed laser as a tool for transient disturbance testing of I2L LSI microcircuits,” IEEE Trans. Sayers, "Comparison of Transient Threshold Levels Induced by Flash X-Rays and Pulsed Lasers", IEEE Trans.