The variation in electrical characteristics of Au/SnO 2/ n-Si (MIS) Schottky diodes have been systematically investigated as a function of temperature by using forward bias current–voltage ( I– V) measurements. The main diode parameters, ideality factor n and zero-bias barrier height Φ B0, were found strongly temperature dependent and while the zero-bias barrier height Φ B0( I– V) increases, the n decreases with increasing temperature. This behavior has been interpreted by the assumption of a Gaussian distribution of barrier heights due to barrier inhomogenities that prevail at the metal–semiconductor interface. The zero-bias barrier height Φ B0 vs q/(2 kT) plot has been drawn to obtain evidence of a Gaussian distribution of the barrier heights, and values of Φ ¯ B 0 = 1.101 eV and σ 0 = 0.158 V for the mean barrier height and zero-bias standard deviation have been obtained from this plot, respectively. Thus a modified ln( I 0/ T 2) − ( q 2 σ 0 2 ) /2 k 2 T 2 vs q/( kT) plot has given mean barrier height Φ ¯ B 0 and Richardson constant ( A *) as 1.116 eV and 127.86 A cm −2 K −2, respectively. The A * value 127.86 A cm −2 K −2 obtained from this plot is in very close agreement with the theoretical value of 120 A cm −2 K −2for n-type Si. Hence, it has been concluded that the temperature dependence of the forward bias I– V characteristics of the Au/SnO 2/ n-Si (MIS) Schottky diode can be successfully explained on the basis of a thermionic emission (TE) mechanism with a Gaussian distribution of the Schottky barrier heights (SBHs). In addition, we have reported a modification by the inclusion of both n and αχ 0.5 δ in the expression of I 0 to explain the positive temperature dependence of Φ B0 against that of energy band-gap of Si. Thus, the values of temperature coefficient of the effective barrier height Φ Bef(−3.64 × 10 −4 eV/K) is very close agreement with the temperature coefficient of Si band-gap (−4.73 × 10 −4 eV/K).