摘要 |
An improved means and method is provided for forming 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 on a semiconductor substrate, providing a patterned mask in which areas of the epitaxial layer are exposed to be etched, etching recesses in the exposed areas to a first depth to leave pedestals beneath the masked areas, and forming a second and third epitaxial layer on the substrate to fill the recesses. The second epitaxial layer is U-shaped and conformally coats the bottom and sides of the recesses. The U-shaped layer acts as the isolation layer separating the first epitaxial layer portions in the pedestals wherein the power devices will be built, from the third epitaxial layer regions 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. |