Low loss substrate for integrated passive devices

Electronic elements (″) having an active device region and integrated passive device (IPD) region on a common substrate preferably include a composite dielectric region (″) in the IPD region underlying the IPD to reduce electromagnetic (E-M) coupling to the substrate. Mechanical stress created by plain dielectric regions (′) and its deleterious affect on performance, manufacturing yield and occupied area may be avoided by providing electrically isolated inclusions (″) in the composite dielectric region (″) of a material having a thermal expansion coefficient (TEC) less than that of the dielectric material (″) in the composite dielectric region (″). For silicon substrates, non-single crystal silicon is suitable for the inclusions (″) and silicon oxide for the dielectric material (″). The inclusions (″) preferably have a blade-like shape separated by and enclosed within the dielectric material (″).