Epitaxially isolated semiconductor device means and method.

摘要

An improved means and method is provided for form- lng isolated device regions suitable for the construction of control circuits and devices, in the presence of and isolated from other device regions suitable for the construction of bottom-contact power devices. In a preferred embodiment the desired structure is obtained by growing a first epitaxial layer (11) on a semiconductor substrate (10), providing a patterned mask (12) in which areas (11b) of the epitaxial layer (11) are exposed to be etched, etching recesses (13) In the exposed areas (11b) to a first depth (13a) to leave pedestals (11d) beneath the masked areas (11a), and forming a second (14) and third (15) epitaxial layer on the substrate (11) to fill the recesses (13). The second epitaxial layer (14) is U-shaped and conformally coats the bottom and sides of the recesses (13). The U-shaped layer (14) acts as the isolation layer separating the first epitaxial layer portions in the pedestals (11d) wherein the power devices will be built, from the third epitaxial layer regions (15b, 25b) which fill in the U, where the control devices will be built. The doping of the power device region, isolation layer, and control circuitry region may be optimized separately.