4 Irradiation Facility and Setup

The heavy-ion species used for the SEE studies on this product were provided and delivered by the TAMU Cyclotron Radiation Effects Facility (3) and the 88-Inch Berkeley Accelerator Space Effects (BASE) Facility (4)(5) using a superconducting cyclotron and advanced electron cyclotron resonance (ECR) ion source. At the fluxes used, ion beams showed good flux stability and high irradiation uniformity over a 1in diameter circular cross sectional area for the in-air station (TAMU). Uniformity is achieved by means of magnetic defocusing. The flux of the beam is regulated over a broad range spanning several orders of magnitude. For these studies ion fluxes of 10⁵ ions / s-cm² were used to provide heavy-ion fluences up to 10⁷ ions / cm².

For these experiments, Silver (⁴⁷Ag), Copper (²⁹Cu) ions were used. In some cases, angles were used to increment the LET_EFF. LET_EFF ranges from 28.9 to 43MeV-cm² / mg. Kinetic energy ranges from 1.25 to 2.47GeV in the vacuum. Ion beam uniformity for all tests were in the range of 90% to 99%.

The DEM-SOT223LDO Demonstration Fixture test board used for the experiments at the TAMU facility is shown in Figure 4-1. Although not visible in this photo, the beam port has a 1mil Aramica ( DuPont®Kevlar®) 1in diameter window to allow in-air testing while maintaining the vacuum within the accelerator with only minor ion energy loss. The air space between the device and the ion beam port window was maintained at 40mm for all runs.

Figure 4-1 Photograph of the TPS73801-SEP Evaluation Board Mounted in Front of the Heavy-Ion Beam Exit Port