max_gate_length

The same span as min_gate_length, bounded from above: the width of a region between chosen walls must not exceed value. GF180 caps an LDMOS channel at 20 µm and the device’s width at 50, and no region carries either on its own — a rectangle has two widths, and only the choice of walls says which is meant.

Semantics, layers, parameters

As min_gate_length, with > in place of <. The LDMOS body is the gate poly over the active with the drift marker taken out, so the walls it shares with the active’s boundary stand at the ends of the channel and the distance between them is the device’s width; the unshared ones stand across it.

Example

- id: MDN.3b
  check: max_gate_length
  layers: [ldnmos_body, ncomp]
  value: 20.0
  params:
    walls: unshared
- id: MDN.4b
  check: max_gate_length
  layers: [ldnmos_body, ncomp]
  value: 50.0