PIN Photodiode Hydrogen Diffusion for 405 nm Sensitivity
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Solution Overview
Problem
PIN photodiodes exhibit poor sensitivity for short-wavelength blue light, particularly at 405 nm, due to high recombination rates and trapping of photo-carriers by silicon dangling bonds on the surface, which affects the conversion and output of photocurrent.
Innovation Solution
The introduction of a manufacturing method involving hydrogen diffusion to terminate silicon dangling bonds on the surface, using a silicon oxide film and silicon nitride film structure, where hydrogen sintering is performed to diffuse hydrogen and bond with the dangling bonds, reducing recombination and enhancing carrier movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PIN photodiode structure is used for blue light detection, then the photodiode can convert light to photocurrent, but the sensitivity for short-wavelength light (405 nm) is poor due to high recombination rates at the silicon surface
Solution Approach 1:
A silicon oxide film is introduced as an intermediary layer between the silicon surface and the external environment. This film passivates the silicon surface by bonding with dangling bonds, reducing the recombination rate of photo-carriers and improving sensitivity for short-wavelength light detection
2Reliability
If the silicon surface is exposed for light detection, then light can be converted to photocurrent, but photo-carriers are trapped by silicon dangling bonds on the surface
Solution Approach 1:
The silicon oxide film acts as a protective intermediary that covers the silicon surface, preventing photo-carriers from being trapped by dangling bonds while still allowing the photodiode to function effectively for light detection
3Productivity
If a conventional manufacturing process is used, then the photodiode can be produced, but sensitivity varies significantly due to manufacturing process dispersion
Solution Approach 1:
The silicon oxide film is formed as a preliminary step in the manufacturing process to passivate the silicon surface before other processing steps. This preliminary action ensures consistent surface conditions across all devices, reducing sensitivity variations caused by manufacturing dispersion
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method significantly improves the sensitivity of PIN photodiodes for short-wavelength light by reducing the trapping of photo-carriers and maintaining high sensitivity even with manufacturing process dispersion, thereby enhancing the photodiode's performance for blue light detection.
Implementation Method 1
hydrogen sintering is performed to diffuse hydrogen and bond with the dangling bonds
Implementation Method 2
silicon oxide film (120) and silicon nitride film (122) form an anti-reflection film
Implementation Method 3
when light with energy higher than the energy ban gap is incident on silicon (Si) having a PIN structure with a reverse bias applied on it, electron-hole pairs are generated
Data Source
AI summary
The objective of this invention is to provide a semiconductor device containing a photodiode and having stable, high sensitivity with respect to short wavelength light near 405 nm, and a manufacturing method for said semiconductor device. PIN photodiode (100C) has the following layers formed on silicon substrate (110): p-type silicon region (112), n-type silicon layer (114), field oxide film (118), silicon oxide film (120c) that covers the surface of the active region, and silicon nitride film (122c) that covers silicon oxide film (120c). Said field oxide film (118) contains extending portions (160) extending to the interior of the active region; the side portions of extending portions (160) are connected to silicon oxide film (120c), and the exposed surface portions of extending portions (160) become regions for hydrogen diffusion.