PROCEDE DE FORMATION DANS UNE PLAQUETTE DE SILICIUM D'UN CAISSON ISOLE

• Main Author: ANCEAU CHRISTINE
• Format: Patent
• Language: French
• Published: 03.01.2003
• Edition: 7
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

Insulating layer and thin monocrystalline silicon layer are removed from an area of a silicon on insulator structure. Epitaxial layer (24, 25) is grown on the entire structure upper surface to provide active layer for wells and power components outside the well region. After planarizing, vertical insulating wall (29) is formed at base of periphery of thin insulating layer support portion (21). Removal of the thin monocrystalline silicon layer and the thin insulating layer by etching comprises: (a) forming a first material layer that is selectively etchable with respect to silicon; (b) depositing and locating a photosensitive resin mask; (c) etching the first material layer and the thin silicon layer; (d) depositing a new resin layer having an extension with respect to the layers already etched; (e) etching the thin insulating layer under the new resin layer; and (f) removing the resin layer and the remaining upper part of the first material layer. The thickness of the epitaxial layer is above 10 microns , preferably 40-60 microns . The insulating layer and the first material layer are silicon oxide. Preferably, the thin monocrystalline silicon layer is strongly doped with a selected type of conductivity, and the epitaxial layer is weakly doped with dopant of the same conductivity type.