Semiconductor structure incorporating thin film transistors with undoped cap oxide layers
First Claim
1. A field effect transistor (FET) structure, comprising:
- a) a first insulator layer containing at least one primary level stud extending through the layer;
b) an undoped cap oxide layer disposed over the insulator layer, and abutting the upper region of each stud;
c) a primary level thin film transistor (TFT) disposed over the undoped cap oxide layer; and
d) a planarized dielectric layer disposed over the thin film transistor.
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Accused Products
Abstract
An improved field effect transistor (FET) structure is disclosed. It comprises a first insulator layer containing at least one primary level stud extending through the layer; an undoped cap oxide layer disposed over the insulator layer and abutting the upper region of each stud; a primary level thin film transistor (TFT) disposed over the undoped cap oxide layer; and a planarized oxide layer disposed over the TFT. Multiple TFT'"'"'s can be stacked vertically, and connected to other levels of studs and metal interconnection layers. Another embodiment of the invention includes the use of a protective interfacial cap over the surface of tungsten-type studs. The FET structure can serve as a component of a static random access memory (SRAM) cell. Related processes are also disclosed.
119 Citations
24 Claims
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1. A field effect transistor (FET) structure, comprising:
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a) a first insulator layer containing at least one primary level stud extending through the layer; b) an undoped cap oxide layer disposed over the insulator layer, and abutting the upper region of each stud; c) a primary level thin film transistor (TFT) disposed over the undoped cap oxide layer; and d) a planarized dielectric layer disposed over the thin film transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A field effect transistor (FET) structure, comprising:
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a) a first insulator layer containing at least one primary level stud extending through the layer; b) an undoped cap oxide layer disposed over the insulator layer, and abutting the upper region of each stud; c) a primary level thin film transistor (TFT) disposed over the undoped cap oxide layer, said TFT itself comprising; c1) doped polysilicon source and drain regions disposed over a portion of the cap oxide layer and over the exposed upper surface of the stud, wherein the source and drain regions are separated from each other by a channel; c2) a second insulator layer disposed over the channel, source, and drain regions; and c3) a transistor gate electrode disposed over a portion of the second insulator layer, and substantially self-aligned with the channel, wherein a protective, interfacial layer of doped polysilicon is disposed between the lower surface of the source and drain regions and the upper surface of the primary level stud, covering the surface of the stud; and d) a planarized dielectric layer disposed over the TFT. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification