Light-receiving device and method for producing the same

Abstract

A light-receiving device includes a light-receiving layer having an undoped multi-quantum well structure; a cap layer disposed on the light-receiving layer, the cap layer including a semiconductor layer doped with a p-type impurity; a mesa structure including the cap layer; a p-type region extending from the p-type semiconductor layer toward the light-receiving layer, the p-type region including the p-type impurity diffused from the semiconductor layer in the mesa structure; a p-n junction formed at an end of the p-type region; and an electrode disposed on the cap layer of the mesa structure. The mesa structure is defined by a trench surrounding the mesa. The trench has a bottom that reaches the vicinity of an upper surface of the light-receiving layer. The p-n junction is located in the light-receiving layer or at the boundary between the light-receiving layer and the cap layer disposed on the light-receiving layer.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a light-receiving device and a method for producing the same.[0003]2. Description of the Related Art[0004]Living bodies, such as animals and plants, and substances, such as gases associated with the environment, have the characteristics of absorbing specific light in the infrared region including the near-infrared light with a wavelength of about 2 μm to 10 μm. In order to detect the absorption spectra of the substances such as gases associated with environments or organisms such as animals and plants, infrared light-receiving devices and infrared sensing devices including such infrared light-receiving devices are under development. In particular, in the near-infrared to infrared region, the photosensitivity to long-wavelength light is being improved. Here, the infrared light-receiving devices include a light-receiving layer composed of a III-V group compound semiconductor. In the light-...

AI Technical Summary

Benefits of technology

This patent discusses the limitations of two different types of photodiodes: planar-type and mesa-type. Planar-type photodiodes are formed by selective diffusion and have efficiency and sensitivity issues, while mesa-type photodiodes have larger fill factors but are susceptible to leakage current. The text proposes a solution to reduce dark current, which occurs due to crystal damage caused by dry etching, by forming a mesa structure where the edge of a p-n junction is not exposed to the atmosphere. The invention aims to improve the performance of light-receiving devices without requiring a cooling mechanism.

Problems solved by technology

However, the planar-type photodiode formed by selective diffusion has problems described below.

However, it is difficult to uniformly perform selective diffusion over the large-diameter wafer.

(2) If a region in which impurity is not diffused is not sufficiently ensured, it is difficult to separate pixels.

Thus, sensitivity improvement is limited.

In another respect, an increase in pixel pitch density is limited.

The deviation of positions of p-n junctions changes the dependence of sensitivity and response speed on bias voltage, thus affecting the stability of properties of the photodiodes.

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