A Novel Structure of a-SiN:H/a-Si:H Multilayer Avalanche Photodiode (MAPD)

1993 ◽  
Vol 297 ◽  
Author(s):  
Jiao Lihong ◽  
Meng Zhiguo ◽  
Sun Zhonglin

Because of the lower density of interface states in a-Si:H/a-SiN:H than that in a-Si:H/a-SiC:H, an a-Si:H/a-SiN multilayer reach-through avalanche photodiode is fabricated on an ITO/glass substrate by plasma-enhanced chemical vapor deposition (PECVD) . In order to improve the performance of the a-Si:H/a-SiN:H APD'S, a novel structure is used. By controlling the deposition ratio of silicon and nitrogen of amorphous SiN,the valence band top of a-Si:H is deeper than that of a-SiN:H, that is, the a-Si :H/a-SiN: H system has the electron potential well in a-Si:H, while the hole well is in a-SiN:H, thus we can successfully suppress the hole impact ionization, correspondingly enhance the electron impact ionization effectively.The measurement of current versus voltage is employed to study the multiplication factors and the impact ionization coefficients. The characteristics of a-Si:H/a-SiN:H APD's,such as I-V curves, optical gains, impact ionization rates, excess noise factors, the relative response and the relationship between the breakdown voltage and wavelength, are studied. The electron multiplication factor is Mc=4.5 at reverse bias V=12v. An optical gain of 3.7 at reverse bias VR=12v and an incident light power Pin=3μw is obtained. Homo junction a-Si:H reach-through APD's and homojunction a-Si:H APD's are also fabricated for comparison.The results show that the novel a-Si:H/a-SiN:H APD's is promising in high-gain, low-noise photodetectors.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuchen Liu ◽  
Xin Yi ◽  
Nicholas J. Bailey ◽  
Zhize Zhou ◽  
Thomas B. O. Rockett ◽  
...  

AbstractAvalanche Photodiodes (APDs) are key semiconductor components that amplify weak optical signals via the impact ionization process, but this process’ stochastic nature introduces ‘excess’ noise, limiting the useful signal to noise ratio (or sensitivity) that is practically achievable. The APD material’s electron and hole ionization coefficients (α and β respectively) are critical parameters in this regard, with very disparate values of α and β necessary to minimize this excess noise. Here, the analysis of thirteen complementary p-i-n/n-i-p diodes shows that alloying GaAs with ≤ 5.1 % Bi dramatically reduces β while leaving α virtually unchanged—enabling a 2 to 100-fold enhancement of the GaAs α/β ratio while extending the wavelength beyond 1.1 µm. Such a dramatic change in only β is unseen in any other dilute alloy and is attributed to the Bi-induced increase of the spin-orbit splitting energy (∆so). Valence band engineering in this way offers an attractive route to enable low noise semiconductor APDs to be developed.


Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 740
Author(s):  
Gaoming Li ◽  
Xiaolong Zhao ◽  
Xiangwei Jia ◽  
Shuangqing Li ◽  
Yongning He

The avalanche photodiode is a highly sensitive photon detector with wide applications in optical communication and single photon detection. ZnO is a promising wide band gap material to realize a UV avalanche photodiode (APD). However, the lack of p-type doping, the strong self-compensation effect, and the scarcity of data on the ionization coefficients restrain the development and application of ZnO APD. Furthermore, ZnO APD has been seldom reported before. In this work, we employed a p-Si/i-ZnO/n-AZO structure to successfully realize electron avalanche multiplication. Based on this structure, we investigated the band structure, field profile, Current–Voltage (I-V) characteristics, and avalanche gain. To examine the influence of the width of the i-ZnO layer on the performance, we changed the i-ZnO layer thickness to 250, 500, and 750 nm. The measured breakdown voltages agree well with the corresponding threshold electric field strengths that we calculated. The agreement between the experimental data and calculated results supports our analysis. Finally, we provide data on the impact ionization coefficients of electrons for ZnO along the (001) direction, which is of great significance in designing high-performance low excess noise ZnO APD. Our work lays a foundation to realize a high-performance ZnO-based avalanche device.


2020 ◽  
Vol 92 (1) ◽  
pp. 10301
Author(s):  
Tat Lung Wesley Ooi ◽  
Pei Ling Cheang ◽  
Ah Heng You ◽  
Yee Kit Chan

In this work, Monte Carlo model is developed to investigate the avalanche characteristics of GaN and Al0.45Ga0.55N avalanche photodiodes (APDs) using random ionization path lengths incorporating dead space effect. The simulation includes the impact ionization coefficients, multiplication gain and excess noise factor for electron- and hole-initiated multiplication with a range of thin multiplication widths. The impact ionization coefficient for GaN is higher than that of Al0.45Ga0.55N. For GaN, electron dominates the impact ionization at high electric field while hole dominate at low electric field whereas Al0.45Ga0.55N has hole dominate the impact ionization at higher field while electron dominate the lower field. In GaN APDs, electron-initiated multiplication is leading the multiplication gain at thinner multiplication widths while hole-initiated multiplication leads for longer widths. However for Al0.45Ga0.55N APDs, hole-initiated multiplication leads the multiplication gain for all multiplication widths simulated. The excess noise of electron-initiated multiplication in GaN APDs increases as multiplication widths increases while the excess noise decreases as the multiplication widths increases for hole-initiated multiplication. As for Al0.45Ga0.55N APDs, the excess noise for hole-initiated multiplication increases when multiplication width increases while the electron-initiated multiplication increases with the same gradient at all multiplication widths.


2000 ◽  
Vol 10 (01) ◽  
pp. 327-337
Author(s):  
J. C. CAMPBELL ◽  
H. NIE ◽  
C. LENOX ◽  
G. KINSEY ◽  
P. YUAN ◽  
...  

The evolution of long-haul optical fiber telecommunications systems to bit rates greater than 10 GB/s has created a need for avalanche photodiodes (APDs) with higher bandwidths and higher gain-bandwidth products than are currently available. It is also desirable to maintain good quantum efficiency and low excess noise. At present, the best performance (f3dB ~ 15 GHz at low gain and gain-bandwidth product ~ 150 GHz) has been achieved by AlInAs/InGaAs(P) multiple quantum well (MQW) APDs. In this paper we report a resonant-cavity InAlAs/InGaAs APD that operates near 1.55 μm. These APDs have achieved very low noise (k equivalent to 0.18) as a result of the very thin multiplication regions that were utilized. The low noise is explained in terms of a new model that accounts for the non-local nature of impact ionization. A unity-gain bandwith of 24 GHz and a gain-bandwidth-product of 290 GHz were achieved.


Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 148
Author(s):  
Arash Dehzangi ◽  
Jiakai Li ◽  
Manijeh Razeghi

We demonstrate low noise short wavelength infrared (SWIR) Sb-based type II superlattice (T2SL) avalanche photodiodes (APDs). The SWIR GaSb/(AlAsSb/GaSb) APD structure was designed based on impact ionization engineering and grown by molecular beam epitaxy on a GaSb substrate. At room temperature, the device exhibits a 50% cut-off wavelength of 1.74 µm. The device was revealed to have an electron-dominated avalanching mechanism with a gain value of 48 at room temperature. The electron and hole impact ionization coefficients were calculated and compared to give a better prospect of the performance of the device. Low excess noise, as characterized by a carrier ionization ratio of ~0.07, has been achieved.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1497
Author(s):  
Mohamed Fauzi Packeer Mohamed ◽  
Mohamad Faiz Mohamed Omar ◽  
Muhammad Firdaus Akbar Jalaludin Khan ◽  
Nor Azlin Ghazali ◽  
Mohd Hendra Hairi ◽  
...  

Conventional pseudomorphic high electron mobility transistor (pHEMTs) with lattice-matched InGaAs/InAlAs/InP structures exhibit high mobility and saturation velocity and are hence attractive for the fabrication of three-terminal low-noise and high-frequency devices, which operate at room temperature. The major drawbacks of conventional pHEMT devices are the very low breakdown voltage (<2 V) and the very high gate leakage current (∼1 mA/mm), which degrade device and performance especially in monolithic microwave integrated circuits low-noise amplifiers (MMIC LNAs). These drawbacks are caused by the impact ionization in the low band gap, i.e., the InxGa(1−x)As (x = 0.53 or 0.7) channel material plus the contribution of other parts of the epitaxial structure. The capability to achieve higher frequency operation is also hindered in conventional InGaAs/InAlAs/InP pHEMTs, due to the standard 1 μm flat gate length technology used. A key challenge in solving these issues is the optimization of the InGaAs/InAlAs epilayer structure through band gap engineering. A related challenge is the fabrication of submicron gate length devices using I-line optical lithography, which is more cost-effective, compared to the use of e-Beam lithography. The main goal for this research involves a radical departure from the conventional InGaAs/InAlAs/InP pHEMT structures by designing new and advanced epilayer structures, which significantly improves the performance of conventional low-noise pHEMT devices and at the same time preserves the radio frequency (RF) characteristics. The optimization of the submicron T-gate length process is performed by introducing a new technique to further scale down the bottom gate opening. The outstanding achievements of the new design approach are 90% less gate current leakage and 70% improvement in breakdown voltage, compared with the conventional design. Furthermore, the submicron T-gate length process also shows an increase of about 58% and 33% in fT and fmax, respectively, compared to the conventional 1 μm gate length process. Consequently, the remarkable performance of this new design structure, together with a submicron gate length facilitatesthe implementation of excellent low-noise applications.


2012 ◽  
Vol 717-720 ◽  
pp. 1199-1202
Author(s):  
Akin Akturk ◽  
Marc Dandin ◽  
Alexey V. Vert ◽  
Stanislav I. Soloviev ◽  
P. Sandvik ◽  
...  

We report measurements and modeling of silicon carbide (SiC) based ultraviolet photodetectors for the detection of light in the mid-to-short ultraviolet range where SiC’s absorption coefficients are high and the corresponding penetration depths are low. These large absorption coefficients result in increased susceptibility of photo-generated electron and holes to surface recombination and therefore give rise to lower quantum efficiencies. To increase responsivity and extend the detection capability of these photodetectors to short ultraviolet wavelengths (or UVC), we measure an existing silicon carbide avalanche photodiode (APD) designed and fabricated for 280 nm operation by General Electric Global Research Center, and then develop models and techniques to increase their operation range to lower UV wavelengths. The measurements aid the development and calibration of a silicon carbide modeling and design suite that is currently being used to assist the design of a new silicon carbide APD for UVC detection. Here the design considerations require low operating voltages, low noise, low dark count rate and high responsivity. We plan to satisfy design criteria by engineering thickness and doping of stacked layers as well as by designing an APD surface that gives rise to minimal recombination of electrons and holes generated by the incident light.


2020 ◽  
Vol 59 (7) ◽  
pp. 1980 ◽  
Author(s):  
Runqi Wang ◽  
Yang Tian ◽  
Qian Li ◽  
Yanli Zhao

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 567-572
Author(s):  
Joseph W. Parks ◽  
Kevin F. Brennan

A boundary condition specifically designed to model open-circuited devices in a macroscopic device simulator is introduced. Other simulation techniques have relied on an external circuit model to regulate the current flow out of a contact thus allowing the potential to remain the controlled variable at the boundary. The limitations of these methods become apparent when modeling open-circuited devices with an exceptionally small or zero output current. In this case, using a standard ohmic-type Dirichlet boundary condition would not yield satisfactory results and attaching the device to an arbitrarily large load resistance is physically and numerically unacceptable. This proposed condition is a true current controlled boundary where the external current is the specified parameter rather than the potential. Using this model, the external current is disseminated into electron and hole components relative to their respective concentration densities at the contact. This model also allows for the inclusion of trapped interface charge and a finite surface recombination velocity at the contact. An example of the use of this boundary condition is performed by modeling a silicon avalanche photodiode operating in the flux integrating mode for use in an imaging system. In this example, the device is biased in steady-state to just below the breakdown voltage and then open-circuited. The recovery of the isolated photodiode back to its equilibrium condition is then determined by the generation lifetime of the material, the quantity of signal and background radiation incident upon the device, and the impact ionization rates.


2008 ◽  
Vol 1076 ◽  
Author(s):  
Koushik Banerjee ◽  
Shubhrangshu Mallick ◽  
Siddhartha Ghosh ◽  
Elena Plis ◽  
Jean Baptiste Rodriguez ◽  
...  

ABSTRACTMid-wavelength infrared (MWIR) avalanche photodiodes (APDs) were fabricated using Indium Arsenide- Gallium Antimonide (InAs-GaSb) based strain layer superlattice (SLS) structures. They were engineered specifically to have either electron or hole dominated ionization. The gain characteristics and the excess noise factors were measured for both devices. The electron dominated p+-n−-n APD with a cut-off wavelength of 4.13 μm at 77 K had a maximum multiplication gain of 1800 measured at -20 V while that of the hole dominated n+-p--p structure with a cut-off wavelength of 4.98 μm at 77 K was 21.1 at -5 V at 77 K. Excess noise factors were measured between 1-1.2 up to a gain of 800 and between 1-1.18 up to a gain of 7 for electron and hole dominated APDs respectively.


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