This paper presents InP-based evanescently-coupled waveguide modified uni-traveling carrier photodiodes (MUTC-PDs) with a record-breaking 3-dB bandwidth exceeding 220 GHz. The design and fabrication of these photodiodes focus on optimizing carrier transport and optical coupling through careful design of the cliff layer and waveguide layer. The use of benzocyclobutene (BCB) beneath the PD electrodes significantly reduces parasitic capacitance, thereby improving the RC-limited bandwidth. The devices, with sizes of 2×7 μm² and 2×10 μm², achieve 3-dB bandwidths over 220 GHz and external responsivities of 0.161 A/W and 0.237 A/W, respectively. The 2×15 μm² device achieves a peak RF output power of -1.69 dBm at 215 GHz. The design of the InGaAs/InP photodiode involves an epitaxial structure with a 180 nm absorption layer and an 80 nm p-doped InGaAs undepleted absorption layer. A 250 nm slightly n-doped InP drift layer is used as a charge compensation layer. The cliff layer, with an optimized doping level of 2×10¹⁷ cm⁻³, is inserted in the drift layer to enhance electron transport and compensate for the space charge effect. The waveguide layer is optimized by tuning the refractive index and thickness to achieve an optimal responsivity of 1.1 A/W. The fabrication process involves a triple-mesa structure with inductively coupled plasma (ICP) dry etch for vertical sidewalls and precise control of the size of p-mesa and waveguide mesa. The device is fabricated with a 30 nm cliff layer and a 2×15 μm² device with a 15 μm length. The use of BCB under the coplanar waveguide (CPW) electrodes reduces parasitic capacitance and improves the RC-limited bandwidth. The characterization of the devices shows a low dark current of around 100 pA under -5 V bias, which is significantly lower than other InGaAs/InP based MUTC-PDs. The internal responsivity of the devices is calculated by measuring the fiber-to-waveguide coupling loss and waveguide propagation loss. The external and internal responsivities of devices with different lengths are measured, showing a high internal responsivity of up to 1.099 A/W for the 2×15 μm² device. The RF characteristics of the devices are investigated using an optical heterodyne setup, showing a frequency response and saturation performance. The 2×7 μm² and 2×10 μm² devices exhibit ultra-fast speeds with a power dropThis paper presents InP-based evanescently-coupled waveguide modified uni-traveling carrier photodiodes (MUTC-PDs) with a record-breaking 3-dB bandwidth exceeding 220 GHz. The design and fabrication of these photodiodes focus on optimizing carrier transport and optical coupling through careful design of the cliff layer and waveguide layer. The use of benzocyclobutene (BCB) beneath the PD electrodes significantly reduces parasitic capacitance, thereby improving the RC-limited bandwidth. The devices, with sizes of 2×7 μm² and 2×10 μm², achieve 3-dB bandwidths over 220 GHz and external responsivities of 0.161 A/W and 0.237 A/W, respectively. The 2×15 μm² device achieves a peak RF output power of -1.69 dBm at 215 GHz. The design of the InGaAs/InP photodiode involves an epitaxial structure with a 180 nm absorption layer and an 80 nm p-doped InGaAs undepleted absorption layer. A 250 nm slightly n-doped InP drift layer is used as a charge compensation layer. The cliff layer, with an optimized doping level of 2×10¹⁷ cm⁻³, is inserted in the drift layer to enhance electron transport and compensate for the space charge effect. The waveguide layer is optimized by tuning the refractive index and thickness to achieve an optimal responsivity of 1.1 A/W. The fabrication process involves a triple-mesa structure with inductively coupled plasma (ICP) dry etch for vertical sidewalls and precise control of the size of p-mesa and waveguide mesa. The device is fabricated with a 30 nm cliff layer and a 2×15 μm² device with a 15 μm length. The use of BCB under the coplanar waveguide (CPW) electrodes reduces parasitic capacitance and improves the RC-limited bandwidth. The characterization of the devices shows a low dark current of around 100 pA under -5 V bias, which is significantly lower than other InGaAs/InP based MUTC-PDs. The internal responsivity of the devices is calculated by measuring the fiber-to-waveguide coupling loss and waveguide propagation loss. The external and internal responsivities of devices with different lengths are measured, showing a high internal responsivity of up to 1.099 A/W for the 2×15 μm² device. The RF characteristics of the devices are investigated using an optical heterodyne setup, showing a frequency response and saturation performance. The 2×7 μm² and 2×10 μm² devices exhibit ultra-fast speeds with a power drop