US 5,399,507 A · Fabrication of mixed thin-film and bulk semiconductor substrate for integrated circuit applications

Abstract

A mixed thin-film and bulk semiconductor substrate (10, 30) for integrated circuit applications is made with two different processes. In the first process, a standard wafer (11) is masked around its periphery (14). The internal unmasked portion (16) is implanted with an insulating species to form a buried dielectric layer (18), thus forming a mixed thin-film and bulk semiconductor substrate. Alternatively, a thin-film wafer may be masked on an internal portion (36) and then etched to expose a portion (40) of the underlying bulk substrate (11') around the periphery of the wafer. An epitaxial layer (50) is then grown to build up the exposed bulk portion to form the mixed substrate. An isolation region (24, 52, 46, 54) is formed at a boundary between the thin-film portion and the bulk portion. Devices (27, 28, 28') having different voltage requirements may then be formed overlying appropriate portions of the mixed substrate.

Claims13

Dependent claims

A method for making a mixed thin-film and bulk substrate for integrated circuit applications, comprising the steps of:

providing a semiconductor substrate having an implant mask overlying a first portion of the semiconductor substrate;
forming a buried dielectric layer underneath a surface of a second portion of the semiconductor substrate;
forming an isolation region at a boundary between the buried dielectric layer in the second portion of the semiconductor substrate and the first portion of the semiconductor substrate;
forming a first device overlying the first portion of the semiconductor substrate;
and
forming a second device having a supply voltage less than 3.3 volts overlying the second portion of the semiconductor substrate.

3 more elements

A method for making a protection device for an integrated circuit, comprising the steps of:

providing a substrate having a first thin-film semiconductor layer, a first buried dielectric layer underlying the first thin film semiconductor layer, and a second semiconductor layer underlying the first buried dielectric layer;
removing a first portion of the first thin-film semiconductor layer and a first portion of the first buried dielectric layer to form an exposed portion of the second semiconductor layer and to leave a remaining portion of the first thin-film semiconductor layer and a remaining portion of the first buried dielectric layer;
forming a second dielectric layer overlying the exposed portion of the second semiconductor layer and the remaining portions of the first thin-film semiconductor layer and the first buried dielectric layer;
removing a portion of the second dielectric layer to form a sidewall spacer at an edge of the remaining portions of the first thin-film semiconductor layer and the first buried dielectric layer;
growing a third semiconductor layer selectively over the exposed portion of the second semiconductor layer such that the sidewall spacer separates the remaining portions of the first thin-film semiconductor layer and the first buried dielectric layer from the third semiconductor layer;
forming an isolation region at the sidewall spacer;
and
forming a protection device overlying the third semiconductor layer, wherein the remaining portion of the first thin-film semiconductor layer may be used to form a low voltage semiconductor device.

5 more elements

Dependencies are inferred from the claim text.

Fabrication of mixed thin-film and bulk semiconductor substrate for integrated circuit applications

Life of this patent

Fabrication of mixed thin-film and bulk semiconductor substrate for integrated circuit applications

Life of this patent

Abstract

Claims13