Abstract: An integrated circuit device includes a gate stack disposed over a substrate. A first L-shaped spacer is disposed along a first sidewall of the gate stack and a second L-shaped spacer is disposed along a second sidewall of the gate stack. The first L-shaped spacer and the second L-shaped spacer include silicon and carbon. A first source/drain epitaxy region and a second source/drain epitaxy region are disposed over the substrate. The gate stack is disposed between the first source/drain epitaxy region and the second source/drain epitaxy region. An interlevel dielectric (ILD) layer disposed over the substrate. The ILD layer is disposed between the first source/drain epitaxy region and a portion of the first L-shaped spacer disposed along the first sidewall of the gate stack and between the second source/drain epitaxy region and a portion of the second L-shaped spacer disposed along the second sidewall of the gate stack.

Abstract: New derivatives of tiacumicin B are disclosed and are presented by the general formula: wherein R is The use of these derivatives as a method for treating cancer or tumor is disclosed. A method of treating cancer or tumor by administrating the patient a composition comprising a therapeutically effective amount of the tiacumicin B is also disclosed.