Semiconductor structure incorporating thin film transistors with undoped cap oxide layers

US5675185A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Bomy Chen · Cupertino, US
• Subhash B. Kulkarni · Peekskill, US
• Jerome B. Lasky · South Burlington, US
• Randy W. Mann · Jericho, US
• Edward J. Nowak · South Burlington, US
• Werner Rausch · Hopewell Junction, US
• Francis R. White · Saint Johnsbury Center, US

Key dates

• Filing date: Sep 29, 1995
• Grant date: Oct 7, 1997
• Expiry date: Sep 29, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002

Abstract

An improved field effect transistor (FET) structure is disclosed. It comprises a first insulator layer containing at least one primary level stud extending through the layer; an undoped cap oxide layer disposed over the insulator layer and abutting the upper region of each stud; a primary level thin film transistor (TFT) disposed over the undoped cap oxide layer; and a planarized oxide layer disposed over the TFT. Multiple TFT's can be stacked vertically, and connected to other levels of studs and metal interconnection layers. Another embodiment of the invention includes the use of a protective interfacial cap over the surface of tungsten-type studs. The FET structure can serve as a component of a static random access memory (SRAM) cell. Related processes are also disclosed.