Sample descriptions & depth profiles

Sample descriptions (.lcm)

Plain text, and the same format RUMP itself reads and writes — pyRUMP round-trips RUMP's files byte-identically.

Sim Reset
Layer 1
 Thick 151 ITO
 Composition In 2 O 3 Sn 0.1 /
Next
 Thick 10 um
 Composition O 4 C 14 H 10 /
Maxpth 200
Foil disable

Command	Meaning
Sim Reset	Start a new sample
Layer 1 / Next	Begin a layer
Thick <v> <unit>	Thickness — see units below
Composition <El> <n> … /	Stoichiometry; the / terminates the list
Sublayer <n>	Force a sublayer count
Sthickness <v> <unit>	Or set sublayer thickness
Equation <name> <params…>	Depth profile
Species <El> <n> … /	What the profile blends toward
Fuzzy <amount> <steps>	Surface roughness
Maxpth <v>	Default sublayer thickness, 10¹⁵ at/cm²
Absorber <n>	First n layers are a dead layer/window, not sample

Thickness units may be a length (A, nm, um), an explicit areal density (/CM2, M/CM2), or a compound name from density.tab. A compound absent from the table silently falls back to silicon's density — which is what makes Thick 151 ITO come out at 75.5 × 10¹⁵ at/cm² in both RUMP and pyRUMP.

Commands pyRUMP does not implement (plotting, buffers, the G_* global-profile subsystem) are collected in script.ignored rather than raising, so a real file still loads.

Depth profiles

A layer can vary with depth instead of being uniform:

 Equation Linear 0 0.2
 Species Au 1 /

blends from pure matrix at the surface to 20% gold at the back. The mixing rule normalises both compositions first:

composition(x) = f(x)·species_normalised + (1 − f(x))·matrix_normalised

Available: Constant, Linear, Erfc/Error, Exponential, Semi-infinite, Thinfilm, BuriedThinFilm, Thickfilm/Thicfilm, Timedependent, Gaussian/Implant, Edgeworth.

Gaussian, Thinfilm and BuriedThinFilm are integral forms — they place an exact dose per sublayer regardless of how coarse the grid is. The others sample the sublayer centre and need enough sublayers to be accurate; each equation carries a recommended count, which overrides Maxpth.

Spline and Usereqn are not implemented — they need GENPLOT's spline fitter and expression evaluator. They raise rather than silently returning zero.