Suppression of diffusion in epitaxial buried plate for deep trenches
First Claim
1. A semiconductor structure comprising:
- a semiconductor substrate including a vertical stack, from bottom to top, of at least a semiconductor substrate layer having a doping of a first conductivity type at a first dopant concentration at a lower portion thereof, a first-conductivity-type semiconductor layer having dopants of said first conductivity type at a second dopant concentration greater than said first dopant concentration, and a second-conductivity-type semiconductor layer having a doping of a second conductivity type that is the opposite of said first conductivity type;
at least one deep trench capacitor comprising a node dielectric, an inner electrode, and a portion of said second-conductivity-type semiconductor layer, wherein said node dielectric is vertically spaced from said first-conductivity-type semiconductor layer; and
a deep isolation trench vertically extending through said second-conductivity-type semiconductor layer and at least partly into said first-conductivity-type semiconductor layer.
4 Assignments
0 Petitions
Accused Products
Abstract
Dopants of a first conductivity type are implanted into a top portion of a semiconductor substrate having a doping of the first conductivity type to increase the dopant concentration in the top portion, which is a first-conductivity-type semiconductor layer. A semiconductor material layer having a doping of the second conductivity type, a buried insulator layer, and a top semiconductor layer are formed thereupon. Deep trenches having a narrow width have a bottom surface within the second-conductivity-type semiconductor layer, which functions as a buried plate. Deep trenches having a wider width are etched into the first-conductivity-type layer underneath, and can be used to form an isolation structure. The additional dopants in the first-conductivity-type semiconductor layer provide a counterdoping against downward diffusion of dopants of the second conductivity type to enhance electrical isolation.
16 Citations
20 Claims
-
1. A semiconductor structure comprising:
-
a semiconductor substrate including a vertical stack, from bottom to top, of at least a semiconductor substrate layer having a doping of a first conductivity type at a first dopant concentration at a lower portion thereof, a first-conductivity-type semiconductor layer having dopants of said first conductivity type at a second dopant concentration greater than said first dopant concentration, and a second-conductivity-type semiconductor layer having a doping of a second conductivity type that is the opposite of said first conductivity type; at least one deep trench capacitor comprising a node dielectric, an inner electrode, and a portion of said second-conductivity-type semiconductor layer, wherein said node dielectric is vertically spaced from said first-conductivity-type semiconductor layer; and a deep isolation trench vertically extending through said second-conductivity-type semiconductor layer and at least partly into said first-conductivity-type semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method of forming a semiconductor structure comprising:
-
forming a vertical stack, from bottom to top, of at least a semiconductor substrate layer having a doping of a first conductivity type at a first dopant concentration at a lower portion thereof, a first-conductivity-type semiconductor layer having dopants of said first conductivity type at a second dopant concentration greater than said first dopant concentration, and a second-conductivity-type semiconductor layer having a doping of a second conductivity type that is the opposite of said first conductivity type; forming at least one deep trench capacitor within said vertical stack, wherein each of said at least one deep trench capacitor comprises a node dielectric, an inner electrode, and a portion of said second-conductivity-type semiconductor layer, wherein said node dielectric is vertically spaced from said first-conductivity-type semiconductor layer; and forming a deep isolation trench vertically extending through said second-conductivity-type semiconductor layer and at least partly into said first-conductivity-type semiconductor layer. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
-
Specification