Phosphorous-outgassing-induced threshold voltage in p-channel power MOSFET devices

Fuyu Lin; Richard De Souza; Richard Dynes; Shifeng Lu; Pat Schay; Loren Grizzard; Tim Plutino; David Welches

doi:10.1117/12.324403

27 August 1998 Phosphorous-outgassing-induced threshold voltage in p-channel power MOSFET devices

Fuyu Lin, Richard De Souza, Richard Dynes, Shifeng Lu, Pat Schay, Loren Grizzard, Tim Plutino, David Welches

Proceedings Volume 3509, In-Line Characterization Techniques for Performance and Yield Enhancement in Microelectronic Manufacturing II; (1998) https://doi.org/10.1117/12.324403
Event: Microelectronic Manufacturing, 1998, Santa Clara, CA, United States

Abstract

Electrical parameters such as threshold voltage (Vt), breakdown voltage (BVdss), source-drain current (Idss), and leakage (Igss) for surface p-channel MOSFETs are dependent upon channel doping. It was found that phosphorous out-gassing during anneal from doped ILDO could redope the channel and cause unexpected increases in both Vt and Vt variation. It is believed that the Vt variation results from two separate phosphorous out-gassing related mechanisms. One mechanism is the transport of phosphorous by the ambient gas through the furnace with a gradient from source to load. SCA results have shown that the phosphorous concentration was two orders of magnitude higher at the load end than at the source end, which was also confirmed by SIMS analysis. The other mechanism is diffusion oflocalized phosphorous from the TEOS, which does not difftise into the furnace ambient, but rather lingers between wafers. The corresponding Vt variation within a wafer, mostly caused by the latter localized effect,was measured to be 50 to 200 mV depending on poly implant dose. Lot to lot variations caused by both localized and furnace phosphorous have been found to be even larger. Two process modifications, undoped TEOS and a sandwich process, were made to eliminate the phosphorous out-gassing problem. While undoped TEOS does have the drawback of being unable to getter sodium, it was found that across waferuniformity and across flirnaceuniformity for both processes were substantially improved. Almost no phosphorous was detected by the SCA.

Key words: threshold voltage, phosphorous, anneal, outgassing, and sandwich

Citation Download Citation

Fuyu Lin, Richard De Souza, Richard Dynes, Shifeng Lu, Pat Schay, Loren Grizzard, Tim Plutino, and David Welches "Phosphorous-outgassing-induced threshold voltage in p-channel power MOSFET devices", Proc. SPIE 3509, In-Line Characterization Techniques for Performance and Yield Enhancement in Microelectronic Manufacturing II, (27 August 1998); https://doi.org/10.1117/12.324403

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Semiconducting wafers

Phosphorus

Oxides

Field effect transistors

Plasma enhanced chemical vapor deposition

Doping

Boron

Show All Keywords

Keywords/Phrases

Search In:

Publication Years