With the focus on power, modern processes support two flavors of standard cells: HVT and LVT. HVT stands for High-Vt, where the threshold voltage of the device is made higher than the threshold voltage of the standard-Vt (referred to as SVT cell) by appropriate doping. Higher the threshold voltage, lower is the sub-threshold leakage current. However, the delay of the cell is higher. Typically, the portions of the chip which do not demand high performance, or are idle most of the times are designed using HVT cells to save leakage power at the expense of higher propagation delay.

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