In-situ doped polysilicon using vapor dopant for high density DRAMs

Author

Tang, T.E.

Author_Institution

Texas Instrum. Inc., Dallas, TX, USA

fYear

1989

fDate

3-6 Dec. 1989

Firstpage

39

Lastpage

42

Abstract

A highly conformal LPCVD (low-pressure chemical vapor deposition) in-situ doped (ISD) polysilicon process, using a low-toxicity vapor dopant source, t-butylphosphine (TBP), is developed in a standard automated horizontal LPCVD furnace for prototyping 16-Mb DRAMs (dynamic RAMs). The dopant incorporation is found to increase with increasing TBP concentration and decreasing deposition temperature. However, the conformality of the ISD polysilicon decreases with increasing dopant incorporation. A 700 degrees C anneal is sufficient to activate the dopant. An optimized condition gives uniform deposition over a 75-wafer load with a resistivity less than 1.0 m Omega -cm and a side/top step coverage better than 97%. It can fill 10- mu m-deep, 0.8- by 1.5- mu m-wide trenches without forming any voids.<>

Keywords

DRAM chips; VLSI; annealing; chemical vapour deposition; elemental semiconductors; integrated circuit technology; semiconductor doping; silicon; 16 Mbit; 700 degC; LPCVD; anneal; automated horizontal furnace; deposition temperature; high density DRAMs; in-situ doped; optimized condition; polysilicon process; resistivity; t-butylphosphine; uniform deposition; vapor dopant; Annealing; Boats; Furnaces; Instruments; Optical films; Process design; Random access memory; Semiconductor films; Silicon; Temperature;

fLanguage

English

Publisher

ieee

Conference_Titel

Electron Devices Meeting, 1989. IEDM '89. Technical Digest., International

Conference_Location

Washington, DC, USA

ISSN

0163-1918

Print_ISBN

0-7803-0817-4

Type

conf

DOI

10.1109/IEDM.1989.74223

Filename

74223