Patent ID: 7407851

Claim:
A method of fabricating an electronic device, the method comprising: forming a first dielectric layer on an uppermost surface of a substrate; forming a second dielectric layer over the first dielectric layer; the second dielectric layer having a lower diffusivity rate of oxygen than a diffusivity rate of oxygen through the first dielectric layer; forming a third dielectric layer over the second dielectric layer, the third dielectric layer being of a same or similar dielectric as the first dielectric layer; forming a first dopant region in a first portion of the substrate; subsequent to forming the first dopant region, removing a first portion of the third dielectric layer, the first portion having been located substantially over the first dopant region; using a portion of the third dielectric layer which remains after the first portion is removed to align a second dopant mask; forming a second dopant region in a second portion of the substrate in proximity to the first dopant region; performing at least one annealing step to drive-in at least one of the dopants, the diffusion of oxygen to the surface of the substrate during the annealing step being limited by the second dielectric layer.