Method for making an integrated circuit device including photodiodes
AssigneeSTMicroelectronics S.r.l.
InventorsDanielle A. Thomas, Gilles E. Thomas
Life of this patent
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Abstract
Fast and efficient photodiodes with different structures are fabricated using CMOS process technology by adapting transistor structures to form the diode structures. The anode regions of the photodiodes correspond to either PLDD regions of PMOS transistors or P-wells of NMOS transistors to provide two different photodiode structures with different anode region depths and thus different drift region thicknesses. An antireflective film used on the silicon surface of the photodiodes is employed as a silicide-blocking mask at other locations of the device.
Claims9
A method for making an integrated circuit device on a single semiconductor chip including photodiodes thereon, comprising:
- providing a substrate;
- growing an epitaxial layer on the substrate, the epitaxial layer defining an upper silicon surface;
- and
- forming regions of different conductivity type and dopant concentration in the epitaxial layer to define transistors and photodiodes therein, the transistors including a PMOS transistor and an NMOS transistor, the photodiodes including an efficient photodiode and a fast photodiode, the PMOS transistor including PLDD regions disposed in an N-well and defining a channel therebetween, the NMOS transistor including NLDD regions disposed in a P-well and defining a channel therebetween, the efficient photodiode including a relatively thin P-type anode region formed above a relatively thick N-type drift region, the fast photodiode including a relatively thick P-type anode region formed above a relatively thin N-type drift region, the P-well of the NMOS transistor and the P-type anode region of the fast photodiode being formed simultaneously using a first boron ion implantation step, the PLDD regions of the PMOS transistor and the P-type anode region of the efficient photodiode being formed simultaneously using a second boron ion implantation step.
A method for making an integrated circuit device on a single semiconductor chip including a photodiode thereon, comprising:
- providing a substrate;
- growing an epitaxial layer on the substrate, the epitaxial layer defining an upper silicon surface;
- forming regions of different conductivity type and dopant concentration in the epitaxial layer to define transistors and a photodiode therein, the transistors including P-type and N-type regions in the epitaxial layer extending from the upper silicon surface to depths therebelow, the photodiode including a P-type anode region in the epitaxial layer extending from the upper silicon surface to a depth therebelow;
- depositing a dielectric film on the device, the dielectric film being transparent to radiation at a wavelength to which the photodiode is responsive;
- selectively removing portions of the dielectric film to expose silicon surfaces where silicide contact layers are to be formed including over the P-type and N-type regions of the transistors, and retaining the dielectric film over silicon surfaces where silicidation is to be prevented;
- and
- forming silicide contact layers on the exposed silicon surfaces;
- wherein the dielectric film serves as a silicide-blocking mask for the silicon surfaces where silicidation is to be prevented and an antireflective film for the photodiode.
Dependencies are inferred from the claim text.