Abstract: The disclosure relates to the making of the source and drain access regions of a field-effect transistor, these two regions being differentiated. The control region is defined by means of a three-layer mask of metal, resin and metal. A resin mask protects the drain access region, thus enabling the implantation of the source access region. After the dissolving of the resins, the drain access region is implanted.

Abstract: An LPCVD deposition process for depositing doped thin films on a substrate is provided. The process may be performed in a LPCVD reaction chamber at elevated temperatures and reduced pressures. The process is especially suited to the deposition and doping of chemically incompatible deposition species and dopants such as polysilicon and arsenic. A deposition gas (e.g. silane) and a dopant gas (e.g. arsine) are thermally decomposed in the reaction chamber. During the deposition process the gas flows are pulsed relative to one another in some manner. This pulsed gas flows form a multi-layer stack which includes alternating deposition layers and doping layers. The dopants in the doping layer are then diffused during a subsequent annealing step (or during subsequent processing) into the deposition layers to form a uniformly doped thin film.