Semiconductor device including isolation regions

A semiconductor device comprising:

• first active regions on a substrate;
• second active regions on the substrate;
• a first isolation region between the first active regions;
• and
• a second isolation region between the second active regions,
• wherein the first isolation region and the second isolation region each comprise a first insulating material,
• wherein the first isolation region further comprises a second insulating material, wherein the first isolation region comprises a first portion formed of the first insulating material and a second portion formed of the second insulating material,
• wherein the first portion is closer than the second portion to one of the first active regions, and
• wherein the second insulating material is different from the first insulating material.

A semiconductor device comprising:

• active regions disposed on a substrate;
• and
• an isolation region between the active regions,
• wherein the isolation region comprises a first portion formed of a first insulating material, and a second portion formed of a second insulating material having characteristics different from those of the first insulating material,
• wherein the first portion is closer than the second portion to one of the active regions, and
• wherein a bottom surface of the second portion has a first height relative to the substrate that is different from a second height relative to the substrate of a bottom surface of the first portion.