Temperature-independence-point properties for 0.1 μm-scale pocket-implant technologies and the impact on circuit design

The temperature-independence point (TIP) of the drain current for MOS transistors in a 0.1 μm-scale pocket-implant technology is gate-length (L_g) dependent and has different magnitudes for n-MOSFET and p-MOSFET. Circuits such as ring-oscillators have a TIP, lying between the values for nand pMOSFET. The circuit TIP Is close to the n-MOSFET TIP for long L_g and gets closer to the p-MOSFET TIP for short L_g. The reason is the different temperature dependence of electron and hole mobility as a function of L_g. Due to the high field effect, oscillation periods of ring-oscillators with short L_g hardly improve, when the supply voltage is raised beyond the TIP. Therefore, an advantageous supply-voltage (V_DD) choice for pocket-implant technologies is near the TIP of circuits, allowing a favorable combination of short switching delay and minimized temperature dependence. By designing the V_th,p closer to V_th,n, not only the low power dissipation, due to the reduction of the TIP, but also the suppressed TIP fluctuation can be realized.