CRYSTALSIM

initializing lattice

Simon's Law — The Formula

Lesson 4 of 6·20 min read·+75 XP
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A new scaling law for the post-Moore era

Moore's Law described one specific kind of progress: how many transistors fit on a chip when you make each one smaller. It worked for fifty years, then physics hit back — quantum tunneling, leakage, heat. Simon's Law describes a different kind of progress: how chip performance scales when you instead improve the quality of the crystal medium and the efficiency of the electromagnetic coupling driving it.

Key Concept
Simon's Law of Crystal-Electromagnetic Scaling
As crystal lattice purity and electromagnetic coupling efficiency improve, transistor switching performance scales proportionally to the product of the piezoelectric coefficient and the EM coupling factor of the crystal medium, independent of physical transistor size.

Formally:

> P(t) = P_Si(t) · CEF > > P_Si(t) = P₀ · 2^((t − t₀)/τ_eff) > CEF = (μ_crystal/μ_Si) · (1 + κ · η_EM)

where - P_Si(t) — silicon-equivalent trajectory (τ_eff > 2 yr, typically 3–5 post-2020) - μ_crystal/μ_Si — mobility ratio (dimensionless material multiplier) - κ — piezo gating contribution = clamp01(d₃₃·σ_max/V_th) - η_EM — EM coupling efficiency = clamp01(Q/Q_critical), Q_critical ≈ 100 - ECCF = κ · η_EM (both clamped to [0,1] before multiplication)

The key structural difference from Moore's Law: silicon's curve is amplified by a quality factor (CEF) you can keep improving without shrinking anything.

Key Concept
d₃₃ (piezoelectric coefficient)
How much electric polarisation (charge per unit force) a crystal produces under stress along its polar axis, in pC/N. Quartz ≈ 2.3, AlN ≈ 6, ZnO ≈ 12, GaN ≈ 18, PZT ≈ 380. Higher d₃₃ → bigger gate response per unit of EM input.
Key Concept
ECCF (preview — full breakdown next lesson)
A 0–1 figure of merit combining quality factor (Q), resonant amplification, and impedance match between the EM source and the crystal. ECCF = 1 means every joule of EM input becomes mechanical strain on the crystal. We unpack ECCF in Lesson 5.
Interactive · Simon's Law simulator
P(t) = P_Si(t) · CEF
P_Si = P₀·2^(t/τ_eff) · CEF = (μ_crystal/μ_Si)·(1 + κ·η_EM)
κ = 1.000 ·  η_EM = 1.000 ·  ECCF = 1.000 ·  CEF = 2.86
presets:
years from nowperformance (log)Simon's LawMoore's Lawcrossover ~yr 0
P @ yr 5
769.1
P @ yr 10
2.1K
P @ yr 15
5.6K
Bigger gears vs better gears
Moore's Law was making the bicycle smaller — at some point you can't fit on it. Simon's Law is making the *gears* themselves more efficient — a 21-speed bike with the same frame outruns a fixed-gear no matter how light the frame is.
Checkpoint · +5 XP
Why is the base of Simon's Law `(d₃₃ · ECCF)` instead of a constant `2`?

The key insight (memorise this):

> Moore's Law scales with SIZE. (Make things smaller.) Size has a physical floor — you cannot make a transistor smaller than an atom. > > Simon's Law scales with QUALITY. (Make crystals purer and EM coupling more efficient.) Quality has no equivalent floor; the theoretical ceiling on d₃₃ and Q is far above any value reported today.

That asymmetry is why a quality-based scaling law could outlast a size-based one.

Lesson Summary
  • Simon's Law: P(t) = P_Si(t) · CEF, with CEF = (μ_crystal/μ_Si)·(1 + κ·η_EM).
  • P_Si(t) = P₀ · 2^((t−t₀)/τ_eff) with τ_eff > 2 yr (post-2020 deceleration).
  • ECCF = κ · η_EM (both clamped to [0,1]) — dimensionless by construction.
  • Three independent levers: crystal quality (d₃₃), engineering (σ_max, V_th, Q).
Test Your Knowledge · +75 XP
1
Simon's Law (canonical form):
2
d₃₃ measures:
3
Increasing τ_eff (the silicon doubling period) does what?
4
The fundamental difference from Moore's Law:
5
Doubling κ·η_EM (=ECCF) does what to CEF?