Different-voltage device manufactured by a CMOS compatible process and high-voltage device used in the different-voltage device
View Patent ↗A method of manufacturing different-voltage devices mainly comprises forming at least one high-voltage well in high-voltage device regions, at least one N-well in low-voltage device regions, at least one P-well in low-voltage device regions, source/drain wells in high-voltage device regions, and isolation wells in isolation regions in a p-type substrate. The breakdown voltage is adjusted by modulating the ion doping profile. Furthermore, parameters of implanting conductive ions are adjusted for implanting conductive ions into both high-voltage device regions and low-voltage device regions. The isolation wells formed in isolation regions between devices are for separating device formed over high-voltage device regions and device formed over low-voltage device regions. The thickness of a HV gate oxide layer is thicker than the thickness of an LV gate oxide layer for modulating threshold voltages of high-voltage devices and low-voltage devices.
1. A different-voltage device, manufactured by a process compatible with a CMOS process, the different-voltage device comprising:
a high-voltage device in a high-voltage region and a low-voltage device in a low-voltage region, wherein the high-voltage device is manufactured with a low-voltage device process, and two additional masks are further added to manufacture the high-voltage device, and a low-voltage gate oxide layer is disposed directly on a high-voltage gate oxide layer in the high voltage region and on a surface of a substrate in the low-voltage region,
wherein the low-voltage gate oxide layer provided on the high-voltage gate oxide layer together with the high-voltage gate oxide layer thereunder serve as a high-voltage gate oxide member of the high-voltage device, and the low-voltage gate oxide layer provided on the surface of the low-voltage device serves as a low-voltage gate oxide member of the low-voltage device,
wherein the high-voltage gate oxide member of the high-voltage device has a height higher than the low-voltage gate oxide member of the low-voltage device,
wherein the depth of a high-voltage well of the high-voltage device is deeper than the depth of a low-voltage well of the low-voltage device,
wherein the high-voltage gate oxide layer in the high-voltage region is higher than the surface of the substrate in the low-voltage region, and
wherein the high-voltage region and the low-voltage region are isolated by a field oxide and an isolation well thereunder, and the isolation well is directly connected between the high-voltage well of the high-voltage device and the low-voltage well of the low-voltage device, types of the low-voltage well and the high-voltage well are complementary.
2. The different-voltage device as claimed in claim 1 , wherein the high-voltage device and the low-voltage device are isolated from each other.
3. A high-voltage device used in a different-voltage device which is manufactured by a process compatible with a CMOS process, wherein a high-voltage device is manufactured with a process of a low-voltage device, two additional masks are further added to manufacture the high-voltage device, and a low-voltage gate oxide layer is disposed directly on a high-voltage gate oxide layer in a high voltage region and on a surface of a substrate in a low-voltage region,
wherein the low-voltage gate oxide layer provided on the high-voltage gate oxide layer together with the high-voltage gate oxide layer thereunder serve as a high-voltage gate oxide member of the high-voltage device, and the low-voltage gate oxide layer provided on the surface of the low-voltage device serves as a low-voltage gate oxide member of the low-voltage device,
wherein the high-voltage gate oxide member of the high-voltage device has a height higher than the low-voltage gate oxide member of the low-voltage device,
wherein the depth of a high-voltage well of the high voltage device is deeper than the depth of a low-voltage well of the low-voltage device,
wherein the high-voltage gate oxide layer in the high-voltage region is higher than the surface of the substrate in the low-voltage region, and
wherein the high-voltage region and the low-voltage region are isolated by a field oxide and an isolation well thereunder, and the isolation well is directly connected between the high-voltage well of the high-voltage device and the low-voltage well of the low-voltage device, types of the low-voltage well and the high-voltage well are complementary.