An apparatus including a contact on a substrate, a dielectric material
overlying the contact, a phase change element overlying the dielectric
material on a substrate, and a heater element disposed in the dielectric
material and coupled to the contact and the phase change element, wherein
a portion of the dielectric material comprises a thermal conductivity less
than silicon dioxide. A method including introducing over a contact formed
on a substrate, a dielectric material, a portion of which comprises a
thermal conductivity less than silicon dioxide, introducing a heater
element through the dielectric material to the contact, and introducing a
phase change material over the dielectric material and the heater element.