A Co/Cu multilayer serves as a base region of an n-Si metal-base structure in spin-valve transistor (SVT). A 215% change in collector current is found in 40 kA/m at 77 K with typical characteristics of a spin-valve effect. The device is biased to inject hot electrons from one Si layer through the multilayer. The sputterbond technology and lithographic process are developed to reduce the dimensions of the device. The technology and the realization of an SVT also establish the feasibility of combining Si technology and spin electronics. The combination of nanomagnetism and nanoelectronics makes it possible to realize new devices and memory functions.