## 2 Radiation in Space and Its Effects on Electronic Components
### A Review of Some TID Radiation Test Results on COTS Components  
In previous works [9], we determined the TID dose for some COTS components working in an ARM board based on the ESA (European Space Agency) standard by conducting a qualification campaign for the processor. We found a weak behavior of the voltage regulator and a good TID result that was in line with previous tests carried out in the same family of devices [10].  
Two recent and extensive technical reports from NASA [11; 12] delve into the use of COTS components in space missions and provide recommendations for their validation and usage. Additionally, a more general explanatory course in [13] is also recommended.  
In [11], the focus is solely on COTS, and it points out that COTS manufactured using newer CMOS/BiCMOS technologies exhibit robust performance in the face of total ionizing dose radiation. This is attributed to the fact that, in newer technologies, the transistor gate area and oxide thickness are reduced, resulting in a lower total number of trap sites for charges generated during a radiation event. Many of the TID effects in MOS devices occur in the insulator element (SiO\({}_{2}\)) and its interface with the semiconductor. The thickness of the dielectric element can vary from 2 nm in the gate to 1000 nm in the field oxide. [PERSON] et al. [14] observe how radiation tolerance can be increased by decreasing that thickness from 10 krad with 40 nm to 500 krad with 20 nm.  
On the other hand, [PERSON] et al's work [12] offers a broader scope and extensively addresses the use of COTS and the effects of TID across different technologies, with numerous references provided for further exploration.  
In the study conducted by [PERSON] et al. [15], a total of four microcontrollers based on FRAM technology and five operational amplifiers, encompassing both CMOS and bipolar designs, underwent total ionizing dose testing. The findings revealed that, in an unbiased mode, the microcontrollers demonstrated impressive TID tolerance, exceeding 490 krad. However, when configured to operate in deep sleep mode, their tolerance significantly decreased to 7.5 krad. On the other hand, the operational amplifiers exhibited varying levels of radiation resistance, with failures occurring at 25, 130, and 190 krad, while one unit remarkably withstood TID testing up to 350 krad.  
In a related study by [16], radiation effects on diverse devices with distinct technologies were investigated at the Goddard Space Flight Center during the years 2020-2021. These devices included those utilizing bipolar, CMOS, and InGaAs/CMOS technologies, subjected to TID testing at levels of 16.3, 17.7, 20, and 50 krad. For the majority of the tested parameters, all devices remained within their specified tolerances, except for one case involving a bipolar voltage regulator. In this instance, the output voltage deviated from the specified range starting at 2.5 krad.  
Furthermore, recent research conducted by [17] focused on TID testing of commercial off-the-shelf-based point-of-load (PoL) converters incorporating GaN high electron mobility transistors. A total of nine boards were manufactured and subjected to testing, with notable results. These PoL converters displayed varying degrees of radiation resistance, with failures occurring at TID levels of 20, 30, and 60 krad.