temperature is much lower: 200C compared with 600C. Hence, the stress
induced by the thermal expansion mismatch between InP and Si is significantly
reduced. For 20-mm-diameter photodiodes on InP, the maximum operating currents
without saturation were 30 mA under 4 V bias, 35 mA under 5 V bias, and 40 mA
under 6 V bias. Thermal failure occurred at 45 mA at 6 V. At bias voltages of 4, 5, and
6 V, the 20-mm photodiode bonded on Si showed very similar saturation behavior as
the photodiode on InP. However, due to better thermal conductivity and larger
specific heat capacity of Si, it could be operated at higher bias voltages of 7 and
8 V, which resulted in higher power dissipation. The highest operating current without
saturation was 50 mA at 8 V