Via in substrate with deposited layer

A semiconductor substrate having:

• (a) a body including a semiconductor material, the body having a first surface;
• (b) an opening having a minor diameter of about 500 μm or less extending into the body from the first surface such that the semiconductor material is exposed at an interior surface of the opening, the interior surface of the opening being comprised of a sidewall surface extending away from the first surface, a bottom surface joined to the sidewall surface, and a plurality of recesses, the interior surface having a first surface roughness of at least 100 nm;
• (c) an insulating layer overlying the interior surface, the insulating layer having a surface roughness of less than 20 nm;
• and
• (d) a smoothing layer, at least portions of the smoothing layer and the body integrally formed with the insulating layer, and at least portions of the smoothing layer disposed within the recesses.

A microelectronic substrate having:

• (a) a body having a first surface;
• (b) an opening extending into the body from the first surface such that material of the body defines an interior surface of the opening, the interior surface being comprised of a sidewall surface extending away from the first surface, a bottom surface joined to the sidewall surface, and a plurality of recesses, the material comprising a semiconductor, the interior surface of the opening having a first surface roughness;
• (c) a monocrystalline smoothing layer overlying the interior surface, the smoothing layer including a glass and having a surface roughness less than the first surface roughness, at least a portion of the smoothing layer being disposed within the recesses;
• and
• (d) an electrically conductive element disposed within the opening so that the smoothing layer is disposed between the conductive element and the body.