he problem of increasing reliability of semiconductor devices under extreme ionizing radiation (electrons, protons, gamma radiation etc.) is relevant. Uses of WCu composite materials with high density and reduced mass-dimension characteristics offer a very attractive alternative to lead protection due to more environmentally friendly composite. W85Cu15 and W75Cu25 composites were obtained by solid-phase synthesis. XRD data showed that the main lines of the WCu spectrum correspond to the body-centered cubic phase of tungsten-copper alloy and the face-centered cubic phase of copper. The W85Cu15 and W75Cu25 composites consist two main phases: W0,6Cu0,4 phase and Cu phase. This may be due to the alloy presence on the outer part of the tungsten grains, which was formed as a result of thermal annealing and copper diffusion during composite synthesis. The most intense peak (110) is maintained when the tungsten concentration changes. The peaks shift towards large angles with a tungsten concentration decreasing in the composite is observed. The intensity of copper peaks increases and a new low-intensity peak appears (220) with the copper concentration increasing in the composite. The shielding properties of the W85Cu15 composite with n- and p-MOS transistors under 1.6÷1.8 MeV electron radiation have been studied. It has been established that maximum shielding efficiency for p-MOS transistors (Ka = 143÷155) have shields with 1.2÷1.5 mm thickness. Shields provide the total absorbed dose reduction up to 6 times for outer space protons (energies from 0.04 to 500 MeV for the 60° orbital inclination and a circular orbit with a height of 300 km).