Integration of analog transistor

摘要

An integrated circuit has two parallel digital transistors and a perpendicular analog transistor. The digital transistor gate lengths are within 10 percent of each other and the analog gate length is at least twice the digital transistor gate length. The first digital transistor and the analog transistor are implanted by a first LDD implant which includes a two sub-implant angled halo implant process with twist angles perpendicular to the first digital transistor gate edge and parallel to the analog transistor gate edge. The second digital transistor and the analog transistor are implanted by a second LDD implant which includes a two sub-implant angled halo implant process with twist angles perpendicular to the second digital transistor gate edge and parallel to the analog transistor gate edge. The first halo dose is at least 20 percent more than the second halo dose.

主权项

1. An integrated circuit, comprising:
a substrate comprising semiconductor material; a first digital transistor, comprising:
a first gate having a first gate length, disposed over said substrate;first lightly doped drain (LDD) regions of a first conductivity type disposed in said substrate, extending partway under said first gate; andfirst halo regions of a second, opposite, conductivity type disposed in said substrate, extending partway under said first gate past said first LDD regions; a second digital transistor, comprising:
a second gate parallel to said first gate having a second gate length within 10 percent of said first gate length, disposed over said substrate;second LDD regions of said first conductivity type disposed in said substrate, extending partway under said second gate; andsecond halo regions of said second conductivity type disposed in said substrate, extending partway under said second gate past said second LDD regions, said first halo regions having an average doping density at least 20 percent more than an average doping density of said second halo regions; and an analog transistor, comprising:
an analog gate perpendicular to said first gate and said second gate having an analog gate length at least twice said first gate length;analog LDD regions of said first conductivity type disposed in said substrate extending partway under said analog gate, an average doping density of said analog LDD regions being at least 75 percent of a sum of average doping densities of said first LDD regions and said second LDD regions; andanalog halo regions of said second conductivity type disposed in said substrate adjacent to said analog gate, not extending past said analog LDD regions under said analog gate, an average doping density of said analog halo regions being at least 75 percent of a sum of said average doping densities of said first halo regions and said second halo regions.