Abstract:
A method of fabricating a MOS transistor with a controllable and modulatable conduction path through a dielectric gate oxide is disclosed, wherein the transistor structure comprises a dielectric oxide layer formed between two silicon plates, and wherein the silicon plates overhang the oxide layer all around to define an undercut having a substantially rectangular cross-sectional shape. The method comprises the steps of: chemically altering the surfaces of the silicon plates to have different functional groups provided in the undercut from those in the remainder of the surfaces; and selectively reacting the functional groups provided in the undercut with an organic molecule having a reversibly reducible center and a molecular length substantially equal to the width of the undercut, thereby to establish a covalent bond to each end of the organic molecule.
Abstract:
A method of controlling the quantity and uniformity of distribution of bonded oxygen atoms at the interface between the polysilicon and the monocrystalline silicon includes carrying out, after having loaded the wafer inside the heated chamber of the reactor and evacuated the chamber of the LPCVD reactor under nitrogen atmosphere, a treatment of the wafer with hydrogen at a temperature generally between 500 and 1200null C. and at a vacuum generally between 0.1 Pa and 60000 Pa. The treatment is performed at a time generally between 0.1 and 120 minutes, to remove any and all the oxygen that may have combined with the silicon on the surface of the monocrystalline silicon during the loading inside the heated chamber of the reactor even if it is done under a nitrogen flux. After such a hydrogen treatment, another treatment is carried out substantially under the same vacuum conditions and at a temperature generally between 700 and 1000null C. with nitrogen protoxide (N2O) for a time generally between 0.1 and 120 minutes.
Abstract:
A method for forming an interface free layer of silicon on a substrate of monocrystalline silicon is provided. According to the method, a substrate of monocrystalline silicon having a surface substantially free of oxide is provided. A silicon layer in-situ doped is deposited on the surface of the substrate in an oxygen-free environment and at a temperature below 700null C. so as to produce a monocrystalline portion of the silicon layer adjacent to the substrate and a polycrystalline portion of the silicon layer spaced apart from the substrate. The silicon layer is heated so as to grow the monocrystalline portion of the silicon layer through a part of the polycrystalline portion of the silicon layer. Also provided is a method for manufacturing a bipolar transistor.