Technological advances in semiconductor integrated circuit (IC) materials, design, processing, and manufacturing have enabled ever-shrinking IC devices, where each generation has smaller and more complex circuits than the previous generation.
As semiconductor circuits composed of devices such as metal-oxide-semiconductor field effect transistors (MOSFETs) are adapted for high voltage applications, problems arise with respect to decreasing voltage performance as the scaling continues with advanced technologies. To maintain high breakdown voltage, large circular transistor designs are used to insulate the transistor drain with a large insulating structure between drain and gate.
With the circular transistor design, the breakdown voltage dictates the size of the transistor. Shrinking the circular transistor using present manufacturing materials and processes is challenging. The circular transistors may be inefficient because the rated driving current for a size to meet the breakdown voltage specification is often much larger than the driving current specification. To reduce the current output, resistors are added in the circuit. The circular transistor is also hard to control, as the threshold voltage often vacillates in a range. A complex control circuit is often used in conjunction with a circular transistor. Thus, a high voltage transistor device having an efficient and scalable design structure while maintaining a high breakdown voltage threshold and a method for making the same in a cost effective manner continues to be sought.
Various embodiments of the present invention will be explained in detail with reference to the accompanying drawings.
USPTO Backgrounds
USPTO Backgrounds