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

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.

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.


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.


2007 ◽  
Vol 556-557 ◽  
pp. 339-342 ◽  
Author(s):  
W.S. Loh ◽  
C. Mark Johnson ◽  
J.S. Ng ◽  
Peter M. Sandvik ◽  
Steve Arthur ◽  
...  

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.


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.


Author(s):  
Seunghyun Lee ◽  
Alireza Kazemi ◽  
Sri Harsha Kodati ◽  
Sen Mathews ◽  
Theodore J. Ronningen ◽  
...  

2006 ◽  
Vol 89 (18) ◽  
pp. 183524 ◽  
Author(s):  
Turgut Tut ◽  
Mutlu Gokkavas ◽  
Bayram Butun ◽  
Serkan Butun ◽  
Erkin Ulker ◽  
...  

2008 ◽  
Vol 600-603 ◽  
pp. 1207-1210
Author(s):  
W.S. Loh ◽  
J.P.R. David ◽  
Stanislav I. Soloviev ◽  
H.Y. Cha ◽  
Peter M. Sandvik ◽  
...  

The hole dominated avalanche multiplication characteristics of 4H-SiC Separate Absorption and Multiplication avalanche photodiodes (SAM-APDs) were determined experimentally and modeled using a local multiplication model. The 0.5x 0.5mm2 diodes had very low dark current and exhibited sharp, uniform breakdown at about 580V. The data agree with modeling result using extrapolated impact ionization coefficients reported by Ng et al. and is probably valid for electric fields as low as ~0.9MV/cm at room temperature provided that both the C-V measurements and electric field determination in this work are correct. The packaged devices demonstrate a positive temperature coefficient of breakdown voltage for temperatures ranging from 100K to 300K which is a desired feature for extreme environment applications.


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