A general process for the functionalization at the 14-position of 13-ketobaccatin derivatives of formula I to give derivatives of formula II wherein the substituents are as defined in the disclosure. The pixel also includes a beneath-holding-portion isolation layer and a pixel isolation layer. A first spacer is formed on the sidewall of the gate structure. Since the voltage level at the distributed header switches is close to the final voltage level, a resulting transient current is small in magnitude.