No, PH3 is not tetrahedral. The shape of the PH3 molecule is trigonal pyramidal.
The electron pair geometry is tetrahedral because there are three bonding pairs and one lone pair. But the molecular geometry is only determined by the bondng pairs of electrons.
Here's more about VSPER theory:
There are five basic electron pair geometries, and their corresponding bond angles. The choice of electron pair geometry depends on the number of electron pairs (whether bonding pairs or lone pairs). The actual molecular geometry is a function of the electron pair geometry.
# electron .. electron pair ................... bond
pairs ........... geometry .........................angl
es
2 ....................linear .............................
..180
3 ....................trigonal planar ...............120
4 ....................tetrahedr
al ......................109.5
5 ....................trigonal bipyramidal ..... 120 and 90
6 ....................octahedra
l .......................90
Electron pair geometries and corresponding molecular geometries
linear
linear
trigonal planar
trigonal planar, bent
tetrahedral
tetrahedral, trigonaly pyramidal, bent
trigonal bipyramidal
trig. bipyramidal, see-saw, T-shaped, linear
octahedral
octahedral, square pyramidal, square planar
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