提供一种形成半导体设备之机制的实施例。半导体设备包含：位于半导体基底上的闸极堆栈。在一些实施例中，半导体设备更包含：半导体组件，例如，电阻器，位于半导体基底上。半导体设备包含：至少位于源极区、汲极区以及闸极堆栈其中之一上的金属硅化物层。半导体设备亦包含：位于半导体组件的一部分中的阻挡区。在一些实施例中，阻挡区包含：第一掺质及原子半径小于第一掺质之第二掺质。

Embodiments of mechanisms for forming a semiconductor device are provided. The semiconductor device includes a gate stack on a semiconductor substrate. In some embodiments, the semiconductor device further includes a semiconductor element, such as for example, a resistor, on the semiconductor substrate. The semiconductor device includes a metal silicide layer on at least one of the gate stack, the source region, and the drain region. The semiconductor device also includes a blocking region in a portion of the semiconductor element. In some embodiments, the blocking region includes first dopants and second dopants with an atomic radius smaller than that of the first dopants.