METHOD FOR PRODUCING A VERTICAL TRANSISTOR IN A TRENCH AND A CORRESPONDING VERTICAL TRANSISTOR

摘要

In order to produce a vertical transistor, a trench (4) is provided whose lateral wall (6) is formed by a monocrystalline semiconductor substrate (2) and whose bottom (8) is formed by a polycrystalline semiconductor substrate (10). A transition region (12) made of an insulating material is placed between the lateral wall (6) and the bottom (8). A semiconductor layer is deposited selective to the material of the transition region (12) whereby enabling an epitaxial semiconductor layer (24) to grow on the lateral wall (6) and a semiconductor layer (26) to grow on the bottom (8), whereby these a space remains between these layers. The deposited semiconductor layers (24, 26) are covered with a thin dielectric (28) that only partially limits a current flow, and the space is filled with a conductive material (30). During a subsequent thermal treatment, dopants diffuse out of the conductive material (30) and into the epitaxial semiconductor layer (26) and form a dopant region (44) therein. The thin dielectric (28) limits the diffusion of the dopants into the semiconductor substrate (2) and prevents the spreading of crystal lattice faults into the epitaxial semiconductor layer (26).