Channel length parameter
lambda is only used in some low level (level=1, 2, 6, 7, 8) spice model files (and with different units: 1/V , cm/√V , or without a unit), in the EPFL-EKV model level=55 (without a unit), as well as in some of the newer - very dedicated - BSIM4 levels (61, 62, and 72), see e.g.
Get foundry model files e.g. from
MOSIS - against registration via a University / High School license account, or use the
PTM model files (scroll down).
Happy New Year to you too!