Browse Prior Art Database

Trench Transistor With Independent Gate Control

IP.com Disclosure Number: IPCOM000061451D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Craig, WJ: AUTHOR

Abstract

The normal source to gate connection used in trench storage node fabrication prevents characterization of the trench transistor for process development or process control in manufacturing. By utilizing a polycrystalline silicon (Poly Si) level to block the formation of the source-to-gate connection, independent gate control is achieved in test devices. This permits the measurement of threshold voltage and sub- threshold conduction of the vertical trench transistor. The cross section shows the essential elements of such a test device. The contact 2, which normally connects the P+ diffusion (source) to the Poly Si 18 in the trench, is broken by the presence of the Poly Si gate electrode 6 during its formation. An oxidation of the Poly Si followed by a reactive ion etch has created the SiO2 insulating separator 8.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Trench Transistor With Independent Gate Control

The normal source to gate connection used in trench storage node fabrication prevents characterization of the trench transistor for process development or process control in manufacturing. By utilizing a polycrystalline silicon (Poly Si) level to block the formation of the source-to-gate connection, independent gate control is achieved in test devices. This permits the measurement of threshold voltage and sub- threshold conduction of the vertical trench transistor. The cross section shows the essential elements of such a test device. The contact 2, which normally connects the P+ diffusion (source) to the Poly Si 18 in the trench, is broken by the presence of the Poly Si gate electrode 6 during its formation. An oxidation of the Poly Si followed by a reactive ion etch has created the SiO2 insulating separator 8. There is a gate SiO2 insulator layer 12 under the gate electrode 6 and on the walls of the trench. Operating characteristics of the trench transistor may now be obtained by making independent connections to the P+ source, the gate electrode 6, the trench Poly Si 18, and the P+ substrate (which acts as a drain in the region 14). The channel region A is activated by potential on the gate electrode 6 and the channel region B of the transistor is then independently activated by a potential applied to the trench Poly Si 18.

1

Page 2 of 2

2

[This page contains 3 pictures or other non-text objects]