Semiconductor memory device and method of forming the same

The present invention relates to a semiconductor memory device and a method of forming the same, and more particularly to a static random access memory having unloaded 4 Tr complementary MOS static random access memory cells. In accordance with the present invention, the gate length and the gate insulation film thickness are different between the p-channel MOS field effect transistors serving as the driver gates and the n-channel MOS field effect transistors forming the flip flop. Namely, the p-channel MOS field effect transistors serving as the driver gates have a larger gate length and a smaller gate oxide film thickness than the n-channel MOS field effect transistors forming the flip flop.