Abstract: A high voltage MOS transistor has a thermally-driven-in first doped region and a second doped region that form a double diffused drain structure. Boundaries of the first doped region are graded. A gate-side boundary of the first doped region extends laterally below part of the gate electrode. The second doped region is formed within the first doped region. A gate-side boundary of the second doped region is separated from a closest edge of the gate electrode by a first spaced distance. The gate-side boundary of the second doped region is separated from a closest edge of the spacer by a second spaced distance. The first spaced distance is greater than the second spaced distance. An isolation-side boundary of the second doped region may be separated from an adjacent isolation structure by a third spaced distance.

Abstract: A high voltage MOS transistor has a thermally-driven-in first doped region and a second doped region that form a double diffused drain structure. Boundaries of the first doped region are graded. A gate-side boundary of the first doped region extends laterally below part of the gate electrode. The second doped region is formed within the first doped region. A gate-side boundary of the second doped region is separated from a closest edge of the gate electrode by a first spaced distance. The gate-side boundary of the second doped region is separated from a closest edge of the spacer by a second spaced distance. The first spaced distance is greater than the second spaced distance. An isolation-side boundary of the second doped region may be separated from an adjacent isolation structure by a third spaced distance.

Abstract: A method of fabricating a high voltage MOS transistor with a medium operation voltage on a semiconductor wafer. The transistor has a double diffused drain (DDD) and a medium operation voltage such as 6 to 10 volts, which is advantageous for applications having both low and higher operation transistor devices. The second diffusion region of the DDD is self-aligned to the spacer on the sidewalls of the gate and gate dielectric, so that the transistor size may be decreased.

Abstract: A method for fabricating a high-voltage MOS transistor. A first doping region with a first dosage is formed in a substrate. A gate structure is formed overlying the substrate and partially covers the first doping region. The substrate is ion implanted using the gate structure as a mask to simultaneously form a second doping region with a second dosage within the first doping region to serve as a drain region and form a third doping region with the second dosage in the substrate to serve as a source region. A channel region is formed in the substrate between the first and third doping regions when the high-voltage MOS transistor is turned on to pass current between the source and drain regions, where a resistance per unit length of the channel region is substantially equal to that of the first doping region. A high-voltage MOS transistor is also disclosed.

Abstract: A method of forming a LDMOS semiconductor device and structure for same. A preferred embodiment comprises forming a first guard ring around and proximate the drain of a LDMOS device, and forming a second guard ring around the first guard ring. The first guard ring comprises a P+ base guard ring, and the second guard ring comprises an N+ collector guard ring formed in a deep N-well, in one embodiment. The first guard ring and second guard ring prevent leakage current from flowing from the drain of the LDMOS device to the substrate.

Abstract: A high voltage MOS transistor has a thermally-driven-in first doped region and a second doped region that form a double diffused drain structure. Boundaries of the first doped region are graded. A gate-side boundary of the first doped region extends laterally below part of the gate electrode. The second doped region is formed within the first doped region. A gate-side boundary of the second doped region is separated from a closest edge of the gate electrode by a first spaced distance. The gate-side boundary of the second doped region is separated from a closest edge of the spacer by a second spaced distance. The first spaced distance is greater than the second spaced distance. An isolation-side boundary of the second doped region may be separated from an adjacent isolation structure by a third spaced distance.

Abstract: A method of forming a LDMOS semiconductor device and structure for same. A preferred embodiment comprises forming a first guard ring around and proximate the drain of a LDMOS device, and forming a second guard ring around the first guard ring. The first guard ring comprises a P+ base guard ring, and the second guard ring comprises an N+ collector guard ring formed in a deep N-well, in one embodiment. The first guard ring and second guard ring prevent leakage current from flowing from the drain of the LDMOS device to the substrate.