Si-based GaN PIN Photodetector Structure

Si-based GaN PIN Photodetector Structure

III-nitrides are suitable for working in extreme conditions due to their excellent radiation hardness and high temperature properties. Therein, the fabrication of various types of GaN-based photodetectors (PDs) has been reported over the past decade. In addition, the high conductivity of silicon substrate has drawn attention to the construction of photodetectors based on GaN on silicon (Si) epitaxial structures. Among all the structures, PIN photodetector structure makes devices with high breakdown voltage, low dark current, sharp cutoff, and high responsivity. PAM-XIAMEN can provide semiconductor wafers, like Si-based PIN photodetector epitaxial structure to meet your requirements. To get more informations of wafers please view Specs of semiconductor photodetector structures epitaxially grown on silicon substrate are listed for example:

GaN Epitaxial Wafer of PIN Photodetector Structure

1. Si-based PIN Photodetector Epitaxial Wafer

No. 1 GaN on Si PIN Epistructure for Photodetector

Layer Thickness Doping Concentration
p+ ~500nm
n-GaN ~5E15cm-3
n+-GaN 1um
Si substrate


No.2 Si-based GaN PIN Photodetector Epitaxial Wafer

Layer Thickness Doping Concentration
pGaN 0.1~0.3um
nGaN 1~1.5um 1E18~5E18
(Al, Ga)N buffer
Si substrate


2. Nitrides for Photodetector Structure Device

Gallium nitride (GaN) and its alloy materials (including aluminum nitride, aluminum gallium nitride, indium gallium nitride, indium nitride) are characterized by their large band gap and wide spectral range (covering from ultraviolet to Infrared full band), high temperature resistance and good corrosion resistance, making it of great application value in the field of optoelectronics and microelectronics. The AlxGa1-xN material system has proven to be very suitable as a photodetector material in the 200-365nm wavelength range. This success has led to the commercialization of nitride-based lateral or vertical structure photodetector. The photodetector structure efficiency is required very high.

3. About PIN Photodetector

A PIN photodetector is formed by adding layers of intrinsic layers between the P-type region and the N-type region of the photodetector. Since the width of the depletion region added to the intrinsic layer is greatly increased, the PIN photodetector is improved. The PN junction of the photodetector structure PIN described below is lateral, so it is called a lateral PIN photodetector. The Si substrate for making the lateral PIN photodetector is undoped, so the substrate resistivity is high. The depletion region is formed on the intrinsic Si substrate. Since the intrinsic substrate is undoped, the PIN photodetector has a relatively wide depletion region, and thus has relatively large quantum efficiency and high responsivity.

However, for the PIN photodetector working principle, the electric field intensity decreases rapidly from the surface to the interior in the lateral structure of the PIN detector, that is to say, most of the electric field intensity is concentrated on the surface of the detector. At low frequencies, the responsivity of the lateral PIN detector is relatively high, but only the photogenerated carriers generated at the surface are fast carriers, which can work at high rates. The carriers generated in the Si substrate reach the electrodes through diffusion movement, which greatly weakens the performance of the PIN photodetector.


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