Shrinking feature sizes, reduced voltages, and higher transistor count of nano-scale silicon chips challenge designers in terms of performance, power consumption, and reliability. This paper investigates the effect of simultaneous use of dynamic voltage and frequency scaling (DVFS) and body biasing (BB) on power consumption, reliability, and performance. An analytical model of reliability as a function of body bias voltage, supply voltage, and frequency is proposed. We derive a three dimensional optimization problem by exploiting proposed reliability model in conjunction with power consumption and performance model. The resulting problem is solved using widely-used geometric optimization to identify optimal supply voltage and body bias voltage and then is validated using accurate simulation. Afterwards, it is demonstrated how joint energy-performance-reliability space optimization method can be used in an adaptive reliability-aware power management systems. Finally, we show that combined soft error aware BB and DVFS is capable of improving power consumption about 30% in comparison to reliability-aware DVFS only for the same level of reliability and performance constraints.