Simple technique for improving the hot-carrier reliability of single-poly bipolar transistors

It is shown experimentally and through simulation that reduced screen oxide thickness leads to increased breakdown voltage of the emitter-base junction (BV/sub ebo/) and reduced peak electric field at breakdown, which translates into improved hot-carrier reliability. The effect of reduced screen oxide thickness on the peak cutoff frequency is minimal. For these devices, thinning the screen oxide from 55 to 35 nm increases BV/sub ebo/ by 0.2 V, improves the hot-carrier-induced excess base current by more than an order of magnitude at a base-emitter voltage of 0.6 V, and degrades the peak cutoff frequency by only 3 percent.