SCRs are a must for ESD protection in low voltagehigh speed I/O as well as ESD protection of RF pads due to least parasitic loading and smallest foot print offered by SCRs. However, conventionally designed SCRs in FinFET and Nanowire technology suffer from very high turn-on and holding voltage. This issue becomes more severe in sub-14 nm non-planar technologies and cannot be handled by conventional approaches like diode- or transient-turn-on techniques. Proposed invention discloses SCR concept for FinFET and Nanowire technology with diffused junction profiles with sub-3V trigger and holding voltage for efficient and robust ESD protection. Besides low trigger and holding voltage, the proposed device offers a 3 times better ESD robustness per unit area.

An insulated gate turn-off thyristor has a layered structure including a p+ layer (e.g., a substrate), an n-epi layer, a p-well, vertical insulated gate regions formed in the p-well, and an n layer over the p-well and between the gate regions, so that vertical npn and pnp transistors are formed. After forming the p-well, boron ions are implanted into the exposed surface of the p-well to form a p+ region. The n-epi layer is then grown over the p-well and the p+ region, and the boron in the p+ region is diffused upward into the n-epi layer and downward to form an intermediate p+ region. The p-well's highly doped intermediate region enables improvement in the npn transistor efficiency as well as enabling more independent control over the characteristics of the n-type layer (emitter) and the overall dopant concentration and thickness of the p-type base to optimize the thyristor's performance.

A semiconductor device includes: a substrate having a cell region and a peripheral region; a thyristor on the cell region; a MOS transistor on the peripheral region; a first shallow trench isolation (STI) between the thyristor and the MOS transistor; and a second STI between the first STI and the MOS transistor. The thyristor further includes: a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a fourth semiconductor layer on the cell region; patterned metal layers in the first semiconductor layer; vertical dielectric patterns on the patterned metal layers; and first contact plugs on the fourth semiconductor layer.

A semiconductor device includes a substrate having a cell region and a peripheral region, a thyristor on the cell region, a MOS transistor on the peripheral region, and a first silicide layer on the substrate adjacent to the thyristor on the cell region. Preferably, the thyristor includes: a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a fourth semiconductor layer on the cell region, vertical dielectric patterns in the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer, and first contact plugs on the fourth semiconductor layer.

A semiconductor device includes: a substrate having a cell region and a peripheral region; a thyristor on the cell region; a MOS transistor on the peripheral region; a first shallow trench isolation (STI) between the thyristor and the MOS transistor; and a second STI between the first STI and the MOS transistor. The thyristor further includes: a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a fourth semiconductor layer on the cell region; patterned metal layers in the first semiconductor layer; vertical dielectric patterns on the patterned metal layers; and first contact plugs on the fourth semiconductor layer.

Thyristor memory cell arrays and their fabrication have improved features. Assist-gates between thyristor memory cells in an array operate on both sides of an assist-gate. The assist-gates can be arranged in various ways for optimized performance and the materials of the assist-gate are selected to control the bias voltage of the assist-gate in operation. The PNPN (or NPNP) thyristor layers of the memory cell can be fabricated in different process flows according to manufacturing concerns and the dopant concentrations of the layers are selected to reduce temperature sensitivity of the memory cell.

A method for fabricating a semiconductor device includes the steps of: providing a substrate having a cell region and a peripheral region; forming a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a fourth semiconductor layer on the substrate; forming a thyristor on the cell region; removing the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer on the peripheral region; and forming a metal oxide semiconductor (MOS) transistor on the peripheral region.

A method for fabricating a semiconductor device includes the steps of: providing a substrate having a cell region and a peripheral region; forming a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a fourth semiconductor layer on the substrate; forming a thyristor on the cell region; removing the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer on the peripheral region; and forming a metal oxide semiconductor (MOS) transistor on the peripheral region.

SCRs are a must for ESD protection in low voltagehigh speed I/O as well as ESD protection of RF pads due to least parasitic loading and smallest foot print offered by SCRs. However, conventionally designed SCRs in FinFET and Nanowire technology suffer from very high turn-on and holding voltage. This issue becomes more severe in sub-14 nm non-planar technologies and cannot be handled by conventional approaches like diode- or transient-turn-on techniques. Proposed invention discloses SCR concept for FinFET and Nanowire technology with diffused junction profiles with sub-3V trigger and holding voltage for efficient and robust ESD protection. Besides low trigger and holding voltage, the proposed device offers a 3 times better ESD robustness per unit area.

Memory arrays of vertical thyristor memory cells with SiGe base layers are described. The composition of the SiGe can be constant or varied depending upon the desired characteristics of the memory cells. The memory cells allow a compact structure with desirable low voltage operations.