Consider the silicon PN junction in Fig. 4-47. P+ Р N N+ 0.4 μm 1.2 μη FIGURE 4-47 (a) If N₁ = 5 × 10¹6 cm³ in the P region and N₁ = 1 × 10¹7 cm³ in the N region, under increasing reverse bias, which region (N or P) will become completely depleted first? What is the reverse bias at this condition? (Hint: use Nap = Non. The doping densities of P+ and N+ are immaterial). (b) Repeat part (a) with N₁ = 1 × 1016 cm³ and Nd = 1 × 10¹7 cm³. (c) What are the small-signal capacitances (F/cm²) at the bias conditions in (a) and (b)?