Abstract:
A semiconductor-on-insulator (SOI) chip. The SOI chip includes a substrate; a buried oxide (BOX) layer disposed on the substrate; an active layer disposed on the BOX layer, the active layer having a first area made from silicon and a second area made from silicon-germanium; a first device fabricated in the first area of the active layer and having a silicon channel and a first threshold voltage; and a second device fabricated in the second area of the active layer and having a silicon-germanium channel and a second threshold voltage differing from the first threshold voltage. Also discussed are alternative forms of the SOI chip and methods of making the SOI chip.
Abstract:
A method of fabricating an integrated circuit provides a transistor having less susceptibility to short channel effects. The transistor utilizes a U-shaped gate conductor and a main gate conductor. The U-shaped gate conductor can provide electrically induced source/drain extensions. The transistor can be a PMOS or NMOS transistor.
Abstract:
A method of fabricating an integrated circuit (IC) with source and drain extension regions. Advantageously, the source and drain extension regions are formed without damage related to integrated circuit implant techniques. Damage is avoided by using solid phase doping to form extension regions. Generally, a doped material is provided adjacent to a transistor gate structure and the IC is annealed. During the annealing process, dopants from the doped material diffuse into the semiconductor substrate to form the source and drain extension regions. The process can be utilized for P-channel or N-channel metal oxide field semiconductor effect transistors (MOSFETs).
Abstract:
In a method for patterning a target material on a semiconductor substrate, a first hardmask material is deposited on the target material and a second hardmask material is deposited on the first hardmask material. The first hardmask material is different from the target material, and the second hardmask material is different from the first hardmask material. A patterned structure of a patterning material such a photoresist material is formed on the second hardmask material. Any exposed region of the second hardmask material is etched such that a second hardmask structure is formed from the second hardmask material remaining under the patterned structure. The etching reactant for etching the second hardmask material to form the second hardmask structure substantially does not etch the first hardmask material. The second hardmask structure is trimmed to reduce the length at each side of the second hardmask structure. Any exposed region of the first hardmask material is etched using a second etching reactant such that a first hardmask structure is formed from the first hardmask material remaining under the second hardmask structure. The second etching reactant substantially does not etch the second hardmask structure and the target material. The first hardmask structure is trimmed with a second trimming reactant to reduce the length at each side of first second hardmask structure. Any exposed region of the target material is etched using a third etching reactant such that a target structure is formed from the target material remaining under the first hardmask structure.
Abstract:
For fabricating a field effect transistor within an active device area of a semiconductor substrate, a gate dielectric is formed on the active device area of the semiconductor substrate, and a gate structure is formed on the gate dielectric with the gate structure being comprised of a first conductive material. A drain spacer comprised of a second conductive material is formed on a first sidewall of the gate structure, and a first liner dielectric is formed between the drain spacer and the first sidewall of the gate structure and between the drain spacer and the semiconductor substrate. A source spacer comprised of the second conductive material is formed on a second sidewall of the gate structure, and a second liner dielectric is formed between the source spacer and the second sidewall of the gate structure and between the source spacer and the semiconductor substrate. Application of at least a drain threshold voltage on the drain spacer with respect to the semiconductor substrate induces charge accumulation in the semiconductor substrate under the first liner dielectric to form a drain extension of the field effect transistor. Similarly, application of at least a source threshold voltage on the source spacer with respect to the semiconductor substrate induces charge accumulation in the semiconductor substrate under the second liner dielectric to form a source extension of the field effect transistor. In this manner, the drain and source extensions of the field effect transistor are electrically induced to have a depth that is shallow regardless of thermal processes used for fabrication of the integrated circuit having the field effect transistor.
Abstract:
For fabricating a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), the MOSFET has a drain region, a source region, and a channel region, and the MOSFET initially has a gate comprised of a capping layer on a polysilicon gate structure disposed on a gate dielectric. A drain silicide is formed in the drain region, and a source silicide is formed in the source region. The drain and source silicides have a first silicide thickness. A first dielectric layer is conformally deposited over the drain region, the source region, and the gate and is polished down until the capping layer of the gate is exposed such that the capping layer and the first dielectric layer are substantially level. A top portion of the first dielectric layer is etched away until sidewalls at a top portion of the polysilicon gate structure are exposed. The capping layer on the polysilicon gate structure of the gate is etched away such that the top of the polysilicon gate structure is exposed. A silicidation metal is deposited to cover the top and the sidewalls of the top portion of the polysilicon gate structure that is exposed. A silicidation anneal is performed with the silicidation metal and the top portion of the polysilicon gate structure to form a gate silicide having a second silicide thickness on top of the polysilicon gate structure. Because the gate silicide is formed from the top and the sidewalls of the top portion of the polysilicon gate structure, the gate silicide has a width that is larger than the width of the polysilicon gate structure. In addition, the gate silicide is formed in a separate step from the step for forming the drain silicide and the source silicide such that the gate silicide may have a larger thickness and be comprised of different metal silicide material from that of the drain silicide and the source silicide.
Abstract:
A method for making a ULSI MOSFET chip includes forming the gate of a transistor on a silicon substrate, covering the gate with a SiON protective layer, and then implanting a pre-amorphization high dose Si or Ge implant into the substrate. Next, dopant is pre-implanted into the substrate to promote subsequent formation of source and drain extensions, with the SiON layer protecting the gate from the pre-amorphization high dose Si or Ge and from the dopant. Undoped polysilicon and polygermanium is then deposited onto the substrate adjacent the gate at relatively low temperatures (600° C.) to establish elevated source and drain regions without excessively thermally stressing the chip. The SiON layer is removed from the gate, and the gate and elevated source and drain regions are implanted with dopant, followed by rapid thermal annealing to form the source and drain extensions in the substrate below the gate. The gate and elevated source and drain regions are then silicidized.
Abstract:
For fabricating a field effect transistor on a semiconductor substrate in SOI (semiconductor on insulator) technology, a pillar of semiconductor material is formed on a layer of buried insulating material. The pillar has a top surface, a left side surface, a right side surface, a front side surface, and a back side surface, and the pillar has a width and a length. A dielectric structure comprised of a hardmask dielectric material is formed on the top surface of the pillar. A first gate dielectric is formed on the left side surface of the pillar, and a second gate dielectric is formed on the right side surface of the pillar, along a gate length of the length of the pillar. A gate electrode material is deposited on the dielectric structure and on the first gate dielectric and the second gate dielectric to surround the pillar at the top surface and the left and right side surfaces of the pillar for the gate length of the pillar. A first gate dopant is implanted at an angle directed toward the gate electrode material on the left side surface of the pillar such that the first gate dopant is not implanted into the gate electrode material on the right side surface of the pillar. In addition, a second gate dopant is implanted at an angle directed toward the gate electrode material on the right side surface of the pillar such that the second gate dopant is not implanted into the gate electrode material on the left side surface of the pillar. The first gate dopant is different from the second gate dopant such that a threshold voltage at the gate electrode material of the field effect transistor is less than about 0.4 Volts. The present invention may be used to particular advantage when the first gate dopant is an N-type dopant, and when the second gate dopant is a P-type dopant.
Abstract:
A method of fabricating an integrated circuit with ultra-shallow source/drain junctions utilizes a dual-amorphization technique. The technique creates a shallow amorphous region and a deep amorphous region 300 nm thick. The shallow amorphous region is between 10-15 nm below the top surface of the substrate, and the deep amorphous region is between 60-120 nm below the top surface of the substrate. The shallow amorphous region helps to reduce ion-implantation channeling effects, and the deep amorphous region helps to getter point defects generated during dopant implantation. The process can be utilized for P-channel or N-channel metal field effects semiconductor transistors (MOSFETS) and has a very low thermal budget.
Abstract:
A method for making a ULSI MOSFET using silicon on insulator (SOI) principles includes masking regions of an amorphous silicon film on a substrate and exposing intended active regions. Laser energy is directed against the intended active regions to anneal these regions without annealing the masked regions, thereby increasing production throughput and decreasing defect density.