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Gate Dielectric Breakdown Avoidance Utilizing Zener Breakdown of Heavily-Doped Junctions

IP.com Disclosure Number: IPCOM000059730D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Poplawski, E: AUTHOR [+2]

Abstract

To protect thin-gate dielectrics, highly-doped N+ to P+ junctions (with Zener breakdown in the 7 to 9 volt range) are formed and connected to all gate electrodes. This Zener-protect diode is fabricated, as shown in Fig. 1, by making an opening in a silicon dioxide (SiO2) layer 2 which overlaps a previously formed N+ junction region in the P substrate 4. Then ion implantation of boron (B+), or like impurity material, is performed. Subsequent process steps result in the structure shown in Fig. 2. These steps include removal of oxide layer 2, plus hot process steps inclusive of depositing another SiO2 layer 6 (which serve also to drive in the P+ implant). A contact hole 8 is opened over the N+ region. Metallization 10 is applied, which is used to connect gate electrodes (not shown) to the N+ region.

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Gate Dielectric Breakdown Avoidance Utilizing Zener Breakdown of Heavily-Doped Junctions

To protect thin-gate dielectrics, highly-doped N+ to P+ junctions (with Zener breakdown in the 7 to 9 volt range) are formed and connected to all gate electrodes. This Zener-protect diode is fabricated, as shown in Fig. 1, by making an opening in a silicon dioxide (SiO2) layer 2 which overlaps a previously formed N+ junction region in the P substrate 4. Then ion implantation of boron (B+), or like impurity material, is performed. Subsequent process steps result in the structure shown in Fig. 2. These steps include removal of oxide layer 2, plus hot process steps inclusive of depositing another SiO2 layer 6 (which serve also to drive in the P+ implant). A contact hole 8 is opened over the N+ region. Metallization 10 is applied, which is used to connect gate electrodes (not shown) to the N+ region. Zener breakdown occurs in the region indicated by Z. The breakdown level is controllable in the 7 to 9 volt range by means such as those described in [*]. In many integrated circuit processes, the steps required to form the Zener-protect diode exist for other reasons, and do not represent additional processing. Reference [*] A. G. Chynoweth and K. G. McKay, Phys . Rev ., 106, 3 (May 1957).

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