Gate electrodes with notches and methods for forming the same

A device, comprising:

• a semiconductor substrate having an active region;
• a device isolation region encircling the active region, wherein the device isolation region comprises a portion of the semiconductor substrate;
• a well region extending into the active region, wherein the device isolation region and the well region are of a same conductivity type;
• and
• a transistor comprising:
• a gate dielectric overlapping the well region;
• and
• a gate electrode over the gate dielectric, wherein the gate electrode comprises:
• a first portion directly over the well region, with the first portion having a first thickness;
• and
• a second portion directly over the device isolation region, wherein the second portion has a second thickness different from the first thickness.

A device, comprising:

• a semiconductor substrate;
• a device isolation region extending into the semiconductor substrate, wherein the device isolation region forms a ring;
• a gate dielectric over the semiconductor substrate;
• a gate electrode over the gate dielectric, wherein the gate electrode comprises:
• a first portion overlapping a portion of the semiconductor substrate encircled by the ring;
• and
• second portions joining to opposing ends of the first portion, wherein the second portions are thinner than the first portion, and wherein the second portions overlap the device isolation region;
• and
• a source region and a drain region in the portion of the semiconductor substrate encircled by the ring.