  We consider the Brans-Dicke theory motivated by the $f(R) = R + \alpha R^n -
\beta R^{2-n}$ model to obtain a stable minimum of the Einstein frame scalar
potential of the Brans-Dicke field. As a result we have obtained an
inflationary scalar potential with non-zero value of residual vacuum energy,
which may be a source of Dark Energy. In addition we discuss the probability of
quantum tunnelling from the minimum of the potential. Our results can be easily
consistent with PLANCK or BICEP2 data for appropriate choices of the value of
$n$ and $\omega$.
