A memory and a method for preparing a memory are provided. The method for preparing the memory includes: providing a substrate, in which the substrate includes a first N-type active region and a first P-type active region; forming an epitaxial layer covering the first P-type active region, in which the epitaxial layer exposes the first N-type active region; simultaneously forming a first gate dielectric layer covering the first N-type active region and a second gate dielectric layer covering the epitaxial layer, in which a thickness of the first gate dielectric layer is substantially the same as a thickness of the second gate dielectric layer; forming a first gate covering the first gate dielectric layer to form a first N-channel Metal Oxide Semiconductor (NMOS) device; and forming a second gate covering the second gate dielectric layer to form a first P-channel Metal Oxide Semiconductor (PMOS) device.

On a semiconductor substrate having an SOI region and a bulk silicon region formed on its upper surface, epitaxial layers are formed in source and drain regions of a MOSFET formed in the SOI region, and no epitaxial layer is formed in source and drain regions of a MOSFET formed in the bulk silicon region. By covering the end portions of the epitaxial layers with silicon nitride films, even when diffusion layers are formed by implanting ions from above the epitaxial layers, it is possible to prevent the impurity ions from being implanted down to a lower surface of a silicon layer.

A method includes: receiving a composite substrate including a first region and a second region, the composite substrate comprising a semiconductor substrate and an insulator layer over the semiconductor substrate; bonding a silicon layer to the composite substrate; depositing a capping layer over the silicon layer; forming a trench through the capping layer, the silicon layer and the insulator layer, the trench exposing a surface of the semiconductor substrate in the first region; growing an initial epitaxial layer in the trench; removing the capping layer to form an epitaxial layer from the silicon layer and the initial epitaxial layer; forming a transistor layer over the epitaxial layer, the transistor layer including a first transistor and a second transistor in the first region and the second region, respectively; and forming an interconnect layer over the transistor layer and electrically coupling the first transistor to the second transistor.

A transistor includes a bulk semiconductor substrate, and first and second raised source/drain regions above the bulk semiconductor substrate. A gate is between the first and second raised source/drain regions. A first dielectric section is beneath the first raised source/drain region in the bulk semiconductor substrate, and a second dielectric section is beneath the second raised source/drain region in the bulk semiconductor substrate. A first air gap is defined in at least the first dielectric section under the first raised source/drain region, and a second air gap is defined in at least the second dielectric section under the second raised source/drain region. The air gaps reduce off capacitance of the bulk semiconductor structure to near semiconductor-on-insulator levels without the disadvantages of an air gap under the channel region.

A semiconductor device includes a substrate that includes peripheral and logic cell regions, a device isolation layer that defines a first active pattern on the peripheral region and second and third active patterns on the logic cell region, and first to third transistors on the first to third active patterns. Each of the first to third transistors includes a gate electrode, a gate spacer, a source pattern and a drain pattern. The second active pattern includes a semiconductor pattern that overlaps the gate electrode. At least a portion of a top surface of the device isolation layer is higher than a top surface of the second and third active patterns. A profile of the top surface of the device isolation layer includes two or more convex portions between the second and third active patterns.

A thin film transistor (TFT) structure. In an example, the TFT includes a gate electrode, a first layer comprising an oxide semiconductor material, and a second layer between the first layer and the gate electrode. The second layer is crystalline and is in contact with the first layer, and includes zirconium and oxygen. The TFT includes a first contact coupled to the first layer at a first location, and a second contact coupled to the first layer at a second location. In some cases, the second layer further includes hafnium. In some cases, the TFT includes a third layer between of the gate electrode and the second layer, the third layer comprising a metal and oxygen. The gate electrode may also include the metal. In some cases, hydrogen is present at an interface between the gate electrode and the second layer.

A semiconductor device includes a substrate and a semiconductor layer. The substrate includes a planar portion and a plurality of pillars on a periphery of the planar portion. The pillars are shaped as rectangular columns, and corners of two of the pillars at the same side of the planar portion are aligned in a horizontal direction or a direction perpendicular to the horizontal direction. The semiconductor layer is disposed over the planar portion and between the pillars.

A semiconductor device including a gate structure on a substrate, a first gate spacer, and a second gate spacer may be provided. A sidewall of the gate structure includes a concave lower sidewall portion and an upper sidewall portion that is vertical with respect to an upper surface of the substrate. The first gate spacer is formed on the upper sidewall portion of the sidewall of the gate structure. The second gate spacer is formed on the concave lower sidewall portion of the sidewall of the gate structure and an outer sidewall of the first gate spacer. The second gate spacer contacts a lower surface of the first gate spacer and includes nitride.

A transistor includes a bulk semiconductor substrate, and a first source/drain region in the bulk semiconductor substrate separated from a second source/drain region in the bulk semiconductor substrate by a channel region. A first air gap is defined in the bulk semiconductor substrate under the first source/drain region, and a second air gap is defined in the bulk semiconductor substrate under the second source/drain region. A gate is over the channel region. A spacing between the first air gap and the second air gap is greater than or equal to a length of the channel region such that the first and second air gaps are not under the channel region. The air gaps may have a rectangular cross-sectional shape. The air gaps reduce off capacitance of the bulk semiconductor structure to near semiconductor-on-insulator levels without the disadvantages of an air gap under the channel region.

Characteristics of a semiconductor device are improved. The semiconductor device is configured to include an SOI substrate including an active region and an element isolation region (element isolation insulating film), a gate electrode formed in the active region via a gate insulating film, and a dummy gate electrode formed in the element isolation region. A dummy sidewall film is formed on both sides of the dummy gate electrode, and is arranged to match or overlap a boundary between the active region and the element isolation region (element isolation insulating film). According to such a configuration, a plug can be prevented from deeply reaching, for example, an insulating layer and a support substrate even when a contact hole is formed to be shifted.