Method of fabricating semiconductor components through implantation and diffusion in a semiconductor substrate
First Claim
1. A method of producing a semiconductor component in a semiconductor substrate, comprising steps:
- a) forming a first well region having a first conductivity type and forming a second well region having a second conductivity type opposite said first conductivity type respectively in said semiconductor substrate;
b) forming at least one trench in said semiconductor substrate; and
c) forming and electrically contacting active regions in said semiconductor substrate;
wherein said forming of said first and second well regions in said step a) comprises steps;
a1) implanting a first well dopant into a first portion of said first well region and implanting a second well dopant into a second portion of said second well region;
a2) diffusing said first well dopant from said first portion partially farther into said first well region and diffusing said second well dopant from said second portion partially farther into said second well region by at least one first drive-in diffusion in a first high temperature drive step carried out before said forming of said at least one trench in said step b); and
a3) diffusing said first well dopant farther into said first well region and diffusing said second well dopant farther into said second well region by at least one second drive-in diffusion in a second high temperature drive step carried out after said forming of said at least one trench in said step b).
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Accused Products
Abstract
A semiconductor element such as a DMOS-transistor is fabricated in a semiconductor substrate. Wells of opposite conductivity are formed by implanting and then thermally diffusing respective well dopants into preferably spaced-apart areas in the substrate. At least one trench and active regions are formed in the substrate. The trench may be a shallow drift zone trench of a DMOS-transistor, and/or a deep isolation trench. The thermal diffusion of the well dopants includes at least one first diffusion step during a first high temperature drive before forming the trench, and at least one second diffusion step during a second high temperature drive after forming the trench. Dividing the thermal diffusion steps before and after the trench formation achieves an advantageous balance between reducing or avoiding lateral overlapping diffusion of neighboring wells and reducing or avoiding thermally induced defects along the trench boundaries.
15 Citations
25 Claims
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1. A method of producing a semiconductor component in a semiconductor substrate, comprising steps:
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a) forming a first well region having a first conductivity type and forming a second well region having a second conductivity type opposite said first conductivity type respectively in said semiconductor substrate; b) forming at least one trench in said semiconductor substrate; and c) forming and electrically contacting active regions in said semiconductor substrate; wherein said forming of said first and second well regions in said step a) comprises steps; a1) implanting a first well dopant into a first portion of said first well region and implanting a second well dopant into a second portion of said second well region; a2) diffusing said first well dopant from said first portion partially farther into said first well region and diffusing said second well dopant from said second portion partially farther into said second well region by at least one first drive-in diffusion in a first high temperature drive step carried out before said forming of said at least one trench in said step b); and a3) diffusing said first well dopant farther into said first well region and diffusing said second well dopant farther into said second well region by at least one second drive-in diffusion in a second high temperature drive step carried out after said forming of said at least one trench in said step b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification