Impurities in Silicon and their Properties

Table 1 lists elements that can act as dopants or impurities in silicon as well as their relevant properties.

Table 1. Silicon Impurities and their Properties

Dopant	Type	Tetrahedral Radius (angstroms)	Misfit Factor	Acceptor Level, distance from valence band (eV)	Donor Level, distance from conduction band (eV)
As	n	1.18	0	-	0.049
P	n	1.1	0.068	-	0.044
Sb	n	1.36	0.153	-	0.039
Al	p	1.26	0.068	0.057	-
B	p	0.88	0.254	0.045	-
Ga	p	1.26	0.068	0.065	-
In	d	1.44	0.22	0.16	-
Ag	d	1.52	0.29	0.89	0.79
Au	d	1.5	0.272	0.57	0.76
Cu	d	1.28	-	0.24, 0.37, 0.52	-
Mo	d	-	-	0.3	-
Ni	d	1.24	-	0.21, 0.76	-
O	d	-	-	-	0.16
Pt	d	-	-	0.42, 0.92	0.85
Ti	d	-	-	0.26	-
Zn	d	-	-	0.31, 0.56	-
Fe	d	1.26	-	-	-

Type d means 'deep impurity'.

Reference: Sorab K. Ghandhi, VLSI Fabrication Principles, Wiley-Interscience

See Also: Diffusion; Ion Implant