Major Physical Properties of Common SiC Polytypes

C.1 Properties

All measurements at room temperature if not specified otherwise. Values taken from [1–19].

Properties/polytype	3C-SiC	4H-SiC	6H-SiC
Stacking sequence	ABC	ABAC	ABCACB
Bandgap (eV)	2.36	3.26	3.02
Exciton gap (eV), 2 K	2.390	3.265	3.023
Lattice constant
(Å)	4.3596	3.0798	3.0805
(Å)	—	10.0820	15.1151
	3.21	3.21	3.21
Electron effective mass
	0.67	0.33	2.0
	0.25	0.42	0.48
Hole effective mass
		1.75	1.85
		0.66	0.66
Number of conduction band minima	3	3	6
Effective density of states in the conduction band (cm−3)	1.5 × 1019	1.8 × 1019	8.8 × 1019
Effective density of states in the valence band (cm`−3)	1.9 × 1019	2.1 × 1019	2.2 × 1019
	0.1
Electron mobility (at low doping)
perpendicular to c-axis		1020	450
parallel to c-axis		1200	100
Hole mobility (at low doping)	100	120	100
Electron saturated drift velocity
Hole saturated drift velocity			1
Breakdown electric field (at )
perpendicular to c-axis	1.4	2.2	1.7
parallel to c-axis	1.4	2.8	3.0
Ionization energy of dopants (meV)
Nitrogen (hexagonal/cubic)	55	61/126	85/140
Aluminum (hexagonal/cubic)	250	198/201	240
Relative dielectric constant
perpendicular to c-axis	9.72	9.76	9.66
parallel to c-axis	9.72	10.32	10.03
Thermal conductivity	3.3–4.9a	3.3–4.9	3.3–4.9
Young modulus (GPa)	310–550	390–690	390–690
Poisson's ratio	0.24	0.21	0.21

^a Estimated values.

C.2 Temperature and/or Doping Dependence of Major Physical Properties

1. 1. Temperature dependence of bandgap [4]

C1

: bandgap at 0 K, : absolute temperature,

1. 2. Doping dependence of carrier mobility (perpendicular to the c-axis) [12–17]

C2

C3

C4

C5

: donor density, : acceptor density given in units of .

n = 2.4∼2.8 for lightly-doped material (10¹⁴∼10¹⁵ cm⁻³), 240 K < T < 600 K

= 1.8∼2.4 for moderately-doped material (10¹⁶∼10¹⁷ cm⁻³), 280 K < T < 600 K

m = 2.2∼2.5 for lightly-doped material (10¹⁴∼10¹⁵ cm⁻³), 240 K < T < 600 K

= 1.8∼2.2 for moderately-doped material (10¹⁶∼10¹⁷ cm⁻³), 280 K < T < 600 K

1. 3. Doping dependence of critical electric field strength (, parallel to the c-axis) [19]

C6

: doping density of the lightly-doped side of the junction (cm⁻¹).

1. 4. Impact ionization coefficients [19, 20]

C7

C8

: electric field strength.

References

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