Production of layer stack on substrate used in manufacture of dynamic random access memory comprises forming mesopores in substrate, forming silicon oxide and bar regions, exposing bar regions, and epitaxially growing silicon on bar regions

摘要

Production of a layer stack made from a silicon oxide layer and a monocrystalline silicon layer on a substrate comprises: forming mesopores in the surface region of substrate; oxidizing the surface to form silicon oxide and bar regions; exposing the bar regions facing away from the substrate; and selectively epitaxially growing the silicon on exposed bar regions opposite the silicon oxide regions. Production of a layer stack made from a silicon oxide layer (11) and a monocrystalline silicon layer (12) on a substrate (2) comprises: forming mesopores (10) in the surface region (3) of the substrate; oxidizing the surface to form silicon oxide and bar regions (22) made from single crystalline silicon which remain between neighboring mesopores; exposing the bar regions facing away from the substrate; and selectively epitaxially growing the silicon on the exposed bar regions opposite the silicon oxide regions. Independent claims are also included for the following: (a) a vertical transistor; and (b) a storage cell. Preferred Features: The process further comprises heat treating to oxidize the silicon bar regions. The bar regions have a diameter of 5-15 nm. The bar regions are exposed by wet chemical etching. The silicon oxide layer is 10-50 nm thick.