scholarly journals Valence band engineering of GaAsBi for low noise avalanche photodiodes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuchen Liu ◽  
Xin Yi ◽  
Nicholas J. Bailey ◽  
Zhize Zhou ◽  
Thomas B. O. Rockett ◽  
...  
Keyword(s):  
Valence Band ◽  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Low Noise ◽  
Excess Noise ◽  
Critical Parameters ◽  
Orbit Splitting ◽  
Band Engineering ◽  
Useful Signal ◽  
The Impact

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.

scholarly journals Estimates of Impact Ionization Coefficients in Superlattice-Based Mid-Wavelength Infrared Avalanche Photodiodes

2003 ◽  
Vol 799 ◽  
Author(s):  
C. H. Grein ◽  
K. Abu El-Rub ◽  
M. E. Flatté ◽  
H. Ehrenreich
Keyword(s):  
Valence Band ◽  
Impact Ionization ◽  
Energy Gap ◽  
Avalanche Photodiodes ◽  
Threshold Energy ◽  
Type Ii ◽  
Band Engineering ◽  
Type Ii Superlattice ◽  
Low Threshold ◽  
Ionization Coefficients

ABSTRACTWe describe band engineering strategies to either enhance or suppress electron-initiated impact ionization relative to hole-initiated impact ionization in type II superlattice mid-wavelength infrared avalanche photodiodes. The strategy to enhance electron-initiated impact ionization involves placing a high density of states at approximately one energy gap above the bottom of the conduction band and simultaneously removing valence band states from the vicinity of one energy gap below the top of the valence band. This gives the electrons a low threshold energy and the holes a high one. The opposite strategy enhances hole-initiated impact ionization. Estimates of the electron (α) and hole (β) impact ionization coefficients predict that α/β>>1 in the first type of superlattice and α/β<<1 in the second type.

Mean multiplication gain and excess noise factor of GaN and Al0.45Ga0.55N avalanche photodiodes

2020 ◽  
Vol 92 (1) ◽  
pp. 10301
Author(s):  
Tat Lung Wesley Ooi ◽  
Pei Ling Cheang ◽  
Ah Heng You ◽  
Yee Kit Chan
Keyword(s):  
Electric Field ◽  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Monte Carlo Model ◽  
Noise Factor ◽  
Excess Noise ◽  
Excess Noise Factor ◽  
Multiplication Gain ◽  
Ionization Coefficients ◽  
The Impact

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.

HIGH SPEED RESONANT-CAVITY InGaAs/InAlAs AVALANCHE PHOTODIODES

2000 ◽  
Vol 10 (01) ◽  
pp. 327-337
Author(s):  
J. C. CAMPBELL ◽  
H. NIE ◽  
C. LENOX ◽  
G. KINSEY ◽  
P. YUAN ◽  
...  
Keyword(s):  
High Speed ◽  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Resonant Cavity ◽  
Multiple Quantum Well ◽  
Low Noise ◽  
Excess Noise ◽  
Multiple Quantum ◽  
Gain Bandwidth ◽  
Unity Gain

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.

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
Keyword(s):  
Reverse Bias ◽  
Impact Ionization ◽  
Incident Light ◽  
Avalanche Photodiode ◽  
Low Noise ◽  
Excess Noise ◽  
Novel Structure ◽  
Ito Glass ◽  
Noise Factors ◽  
The Impact

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.

High-speed and low-noise SACM avalanche photodiodes with an impact-ionization-engineered multiplication region

2005 ◽  
Vol 17 (8) ◽  
pp. 1719-1721 ◽  
Author(s):  
Ning Duan ◽  
Shuling Wang ◽  
Feng Ma ◽  
Ning Li ◽  
J.C. Campbell ◽  
...  
Keyword(s):  
High Speed ◽  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Low Noise

Determination of Impact Ionization Coefficients Measured from 4H Silicon Carbide Avalanche Photodiodes

2007 ◽  
Vol 556-557 ◽  
pp. 339-342 ◽  
Author(s):  
W.S. Loh ◽  
C. Mark Johnson ◽  
J.S. Ng ◽  
Peter M. Sandvik ◽  
Steve Arthur ◽  
...  
Keyword(s):  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Submicron Devices ◽  
Illuminating Light ◽  
Factor Data ◽  
Ionization Coefficients ◽  
P Type ◽  
Dark Currents ◽  
The Impact

Hole initiated avalanche multiplication characteristics of 4H-SiC avalanche photodiodes have been studied. The diodes had n+-n-p SiC epitaxial layers grown on a p-type substrate. These 1 mm2 devices had very low dark currents and exhibited sharp breakdown at voltages of approximately 500V. The diodes multiplication characteristics appeared to be identical when the wavelength of the illuminating light from the top varied from 288 to 325nm, implying that almost pure hole initiated multiplication was occurring. The multiplication factor data were modelled using a local multiplication model with impact ionization coefficients of 4H-SiC reported by various authors. The impact ionization coefficients extracted from submicron devices by Ng et al. were found to give accurate predictions for multiplication factors within the uncertainties of the doping levels. This result suggests that their ionization coefficients can be applied to thicker bulk 4H-SiC structures.

Characterisation of Low Noise 4H-SiC Avalanche Photodiodes

2010 ◽  
Vol 645-648 ◽  
pp. 1081-1084
Author(s):  
James E. Green ◽  
W.S. Loh ◽  
J.P.R. David ◽  
R.C. Tozer ◽  
Stanislav I. Soloviev ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Avalanche Photodiodes ◽  
Depletion Region ◽  
Low Noise ◽  
Excess Noise ◽  
Local Model ◽  
Prior Work ◽  
Absorption Layer ◽  
Impact Ionisation ◽  
Dark Currents

We report photomultiplication, M, and excess noise, F, measurements at 244nm and 325nm in two 4H-SiC separate absorption and multiplication region avalanche photodiodes (SAM-APDs). Sample A is a 4 x 4 array of 16 SAM-APDs. This structure possesses a relatively thin absorption layer resulting in more mixed injection, and consequently higher noise than sample B. The absorption layer of sample B does not deplete, so 244nm light results in >99% absorption outside the depletion region resulting in very low excess noise. Both structures exhibit very low dark currents and abrupt uniform breakdown at 194V and 624V for samples A and B respectively. Excess noise is treated using a local model [1]. The effective ratio of impact ionisation coefficients (keff) is approximately 0.007, this indicates a significant reduction in the electron impact ionisation coefficient, α, compared to prior work [2-5]. We conclude that the value of α will require modification if thick silicon carbide structures are to fit the local model for multiplication and excess noise.

scholarly journals Low Noise Short Wavelength Infrared Avalanche Photodetector Using SB-Based Strained Layer Superlattice

Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 148
Author(s):  
Arash Dehzangi ◽  
Jiakai Li ◽  
Manijeh Razeghi
Keyword(s):  
Short Wavelength ◽  
Room Temperature ◽  
Molecular Beam ◽  
Impact Ionization ◽  
Low Noise ◽  
Excess Noise ◽  
Type Ii ◽  
Type Ii Superlattice ◽  
Strained Layer Superlattice ◽  
Ionization Coefficients

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.

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