AFAIK, there is no specific statement for delta doping. You can define effective thickness of the delta-layer (e.g. 1 nm, or 0.1 nm, or monolayer) and convert 2D delta doping concentration into 3D. Then use regular syntax, for example:

DOPING UNIFORM N.TYPE CONCENTRATION= Y.MIN=0.000 Y.MAX=0.001

Alternatively, you can specify three separate regions for the barrier layer and use DONOR statement, for example:

REGION BOTTOM THICKNESS=0.020 MATERIAL=InAlAs []

REGION BOTTOM THICKNESS=0.001 MATERIAL=InAlAs DONOR= []

REGION BOTTOM THICKNESS=0.004 MATERIAL=InAlAs []

Dmitri Arteev thank you so much Sir