MIMZY · № 19 · the future tool forge

The Silicon Gap

There are three gaps hiding in the question. The band gap of silicon — 1.12 eV — is the real one. The dopants ride in it. And every element that touches the chip is collated below, by the role it plays around the lattice.

forge: MIMZY bench  ·  geometry: № 18 the CMOS gap gate  ·  the 118: ELEMENTS WORKSHOP

I · The gap itself

Silicon is a semiconductor because of a 1.12 eV forbidden band between the valence floor (Ev) and the conduction ceiling (Ec). A dopant works by parking an energy level inside that gap — donors a hair under the ceiling, acceptors a hair above the floor. Click a level to seat it.

The forbidden band

Donors (n-type) sit just below Ec and spill an electron up into the conduction band. Acceptors (p-type) sit just above Ev and pull an electron up out of the valence band, leaving a hole. Deep traps sit mid-gap and kill carriers.

kT at 300 K is 25.9 meV — shallow levels (<~78 meV) ionise fully; indium (160) and the deep traps do not.

II · Everything that rides the lattice

39 elements out of the 118 carry a real, citable job in mainstream silicon CMOS — as the substrate, the dopants, the gate, the wires, the strain, the gases, the light. Filter by role; click any lit cell.

select an
element

39 riders are lit. The dark cells are along for nothing — they never touch the working silicon. Boron, carbon, cobalt and copper — four of David's own folders — ride.

The box you are standing in
This is an educational / simulation instrument — a teaching map of real semiconductor materials science. Every role and every dopant level is from the device-physics literature (Sze). It is a model of which element does what around the silicon, not a process recipe or a SPICE deck. The chemistry is the carbon-real layer; the lattice it serves is the same one № 18 made into a logic gate.
THE GAP IN THE SILICON. Verified before drawing: Si Eg=1.12 eV @300 K; donor levels P 45 / As 54 / Sb 39 meV below Ec; acceptors B 45 / Al 67 / Ga 72 / In 160 meV above Ev; deep traps Au·Fe ~0.55 eV, Pt ~0.42 eV mid-gap.
THE 39 RIDERS · substrate Si · dopants B P As Sb Al Ga In · deep-traps Au Pt Fe · dielectric O N Hf Zr La · gate/barrier Ti Ta W Ru Mo · interconnect/silicide Cu Co Ni · strain Ge C · gases H He F Cl Ar Kr Xe Ne S · EUV light Sn · package Ag Bi Pb.
YOUR FOLDERS THAT RIDE: boron (p-dopant) · carbon (SiC strain · low-k) · cobalt (silicide · advanced contact) · copper (Damascene interconnect).