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Bird's Beak-Free Semi-Rox With Large Radius on Corner Curvature

IP.com Disclosure Number: IPCOM000044108D
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Pan, PH: AUTHOR

Abstract

A semi-recessed oxide (SROX) that is bird's beak free and has a large radius on the curvature of the SROX's corner provides easy B+ field ion implantation (I/I) and low defect density on a Si substrate. A layer of Si with a slope on the sidewall is used to control the diffusion of oxygen, and it results in a large radius in the curvature of the SROX's corner. After a thin pad of SiO2 11 is grown and the Si layer 12 is deposited, as in Fig. 1, a layer of Si3N4 13 is then deposited. The active device region 14 is then defined (Fig. 2), and a Si3N4 spacer 15 is applied to each end of the device region (Fig. 3a). These spacers 15 can be replaced by extending the dimension of the active device region 14, as in Fig 3b.

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Bird's Beak-Free Semi-Rox With Large Radius on Corner Curvature

A semi-recessed oxide (SROX) that is bird's beak free and has a large radius on the curvature of the SROX's corner provides easy B+ field ion implantation (I/I) and low defect density on a Si substrate. A layer of Si with a slope on the sidewall is used to control the diffusion of oxygen, and it results in a large radius in the curvature of the SROX's corner. After a thin pad of SiO2 11 is grown and the Si layer 12 is deposited, as in Fig. 1, a layer of Si3N4 13 is then deposited. The active device region 14 is then defined (Fig. 2), and a Si3N4 spacer 15 is applied to each end of the device region (Fig. 3a). These spacers 15 can be replaced by extending the dimension of the active device region 14, as in Fig 3b. The Si layer 12 is etched by using an etching solution of 7 parts HNO3, 4 parts H2O and 1 part HF or some other etching process to achieve the slope 16 on the sidewall (Fig. 4). The Bfield I/I 17 is then applied (Fig. 5), and thermal oxidation is used to grow the SROX 18 (Fig. 6). After the Si3N4 pad 13 is etched (Fig. 7), an RIE process is used to etch the Si layer 12 (Fig. 8). The residual Si 19 is then oxidized, and the final structure is shown in Fig. 9.

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