Dynamic memory device having a single-crystal transistor on a trench capacitor structure and a fabrication method therefor
US4649625A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 21, 1985 |
| Grant date | Mar 17, 1987 |
| Priority date | — |
| Expiry date | Oct 21, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D88/01
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Dynamic random access memory (DRAM) devices are taught wherein individual cells, including an access transistor and a storage capacitor are formed on a single-crystal semiconductor chip, and more particularly a three-dimensional dynamic random access memory (DRAM) device structure is described having a single-crystal access transistor stacked on top of a trench capacitor and a fabrication method therefor wherein crystallization seeds are provided by the single-crystal semiconductor area surrounding the cell and/or from the vertical sidewalls of the trench and wherein the access transistor is isolated by insulator. In the structure, a trench is located in a p+ type substrate containing heavily doped N+ polysilicon. A composite film of SiO.sub.2 /Si.sub.3 N.sub.4 /SiO.sub.2 is provided for the capacitor storage insulator. A thin layer of SiO.sub.2 is disposed over the polysilicon. A lightly doped p-type epi silicon layer is located over the substrate and SiO.sub.2 layer. The access transistor for the memory cell is located on top of the trench capacitor. An N+ doped material connects the source region of the transistor to the polysilicon inside the trench. A medium doped p-region on …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.