| Electrostatic Discharge (ESD) is one of the common causes of semiconductor device failure. To protect an integrated circuit (IC) from ESD damage, ESD protection circuits should be implemented at each pin of the IC. The ESD protection circuit turns ON to shunt the ESD current during an ESD event, while it remains in the OFF state during the normal IC operation. However, with increasing IC operating frequency, ESD protection circuits at input/output pins would deteriorate the IC performance. ESD protection of high speed RF ICs becomes more challenging.; This dissertation addresses ESD protection in fiber optic receivers, which mainly consist of photodiodes and RF ICs. The ESD protection of a planar p-i-n InGaAs photodiodes is studied. A guard ring (GR) structure is designed and integrated into the photodiode to protect it from ESD damages. Simulation results indicate that the GR can conduct ESD current to discharge the ESD pulse energy. The Human Body Model (HBM) ESD test results prove that a photodiode with a GR protection structure can improve its robustness by 150 V. Test results of the photodiode's capacitance, bandwidth, and nonlinearity indicate that the GR has negligible negative effects on the photodiode's performance.; The feasibility of ESD protection is also investigated for GaAs RF ICs which use the 60 GHz InGaP heterostructure bipolar transistors (HBT) technology. After evaluating the robustness of InGaP HBTs, a novel ESD protection circuit for high speed RF ICs is designed. The circuit is composed of small diodes and large transistors. Two versions of this type of circuits are fabricated. The HBM ESD tests show that these two circuits can withstand 2,700 V and 5,000 V stress, respectively. The RF ICs protected by these two circuits can withstand 3,000 V or 5,000 V HBM ESD stress correspondingly, whereas the RF ICs protected by the conventional diode-based circuit with a similar device size cannot withstand 1,000 V HBM ESD stress. The corresponding impedances of the two circuits at 10 GHz in OFF state, represented by equivalent shunt capacitance and resistance, are 0.22 pF and 500 O for one circuit, and 0.5 pF and 250 O for the other. The circuit with smaller capacitance can be used to protect 10 Gb/s optical receivers. |
