Browse Prior Art Database

Deep Dielectric Isolation

IP.com Disclosure Number: IPCOM000047575D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Malaviya, SD: AUTHOR

Abstract

A submicron size, deep trench isolation may be formed in the single crystal silicon according to the following process. 1. N+ subcollector 12, epitaxial layer 13, thin silicon dioxide layer 14 of about 10-nanometer thickness are formed in and on the P-substrate 10. 2. Photolithography and hardening techniques are used to deposit a hardened photoresist layer 8 in selected areas. 3. Plasma deposit silicon nitride layer 15 of about 400 to 500 nanometers over the entire silicon wafer. 4. Reactive ion etch (RIE) back to form silicon nitride stud at the location where deep trench isolation is desired, as seen in Fig. 1. Strip the photoresist layer 8. Reactive ion etch to remove the oxide layer 14 in all areas except under the silicon nitride stud. 5.

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Deep Dielectric Isolation

A submicron size, deep trench isolation may be formed in the single crystal silicon according to the following process. 1. N+ subcollector 12, epitaxial layer 13, thin silicon dioxide layer 14 of about 10-nanometer thickness are formed in and on the P-substrate 10. 2. Photolithography and hardening techniques are used to deposit a hardened photoresist layer 8 in selected areas. 3. Plasma deposit silicon nitride layer 15 of about 400 to 500 nanometers over the entire silicon wafer. 4. Reactive ion etch (RIE) back to form silicon nitride stud at the location where deep trench isolation is desired, as seen in Fig. 1. Strip the photoresist layer 8. Reactive ion etch to remove the oxide layer 14 in all areas except under the silicon nitride stud. 5. Thermally oxidize the exposed silicon surface to form a silicon dioxide mask 16 for reactive ion etching the isolation trench, as shown in Fig. 2. 6. Remove the silicon nitride layer 15 by wet chemical etching, as seen in Fig. 3. 7. RIE through the silicon dioxide layer 14 and silicon layers 12, to form the deep trench 17 in the silicon, as shown in Fig. 4. 8. P+ boron implant for isolation region 18 as usual. The region 18 may not be needed if the trench 17 is deep enough. 9. Thermally oxidize the exposed silicon until the trench 17 is filled with silicon dioxide material 19. The silicon dioxide 20 growth at the surface may be reactive ion etched back if it is too thick. Otherwise, layer 20 can b...