<title>Possibility of explanation of the noise-factor anomal dependence on carriers multiplication factor (photogain) in threshold avalanche photodetectors based on MIS-type heterostructures at the expense</title>

Abstract

A physical model for explanation of experimentally observed effect of avalanche noise-factor F decrease in MIS-type heterostructures upon a multiplication factor increase is offered. The model is based on the assumption that carriers are retarded near heteroboundary due to trapping by a potential well (for a example in Si02/Si and Ti02/Si) or by surface levels. The calculation results correlate numerically with the experimental data.

Physical Design Fundamentals of High-Performance Avalanche Heterophotodiodes with Separate Absorption and Multiplication Regions

“…At the same time, for presented in Fig. 9 Ge, Si and GaP, function c(Е) (see relations (33) and (45)) in range of fields where α(Е) and β(Е) vary in several orders of magnitude (Okuto & Crowell, 1975), remains, as it follows from (33) and 45, of the order of unity. Calculations based on experimental dependences α(Е) and β(Е) (Cook et al, 1982) show that in InP value c(Е) is some more closely to 1.…”

“…The fact is that dependence α(Е) in InSb was quite well known already in 1967 (Baertsch, 1967), but no one could obtain information about dependence β(Е) (Dmitriev et al, 1987), (Dmitriev et al, 1983), (Dmitriev et al, 1982), (Gavrjushko et al, 1968). Substituting in (45) dependence α(Е) for InSb (Baertsch, 1967), (Dmitriev et al, 1983), (Dmitriev et al, 1982), (Gavrjushko et al, 1968), we find that ratio K = β(E) / α(E) is vanishingly small up to electric field E ≅ 4 × 10 4 V/cm resulting in extremely high value n рВ when at the same time value n nВ is extremely small. It means that M n (V ) becomes much larger than unity, even at voltages V b noticeably lower avalanche breakdown voltage V BD , and value M p (V ) remains equal to unity up to values V b very close to V BD .…”

“…In (45) and below in this Section 3.5 is accepted (unless otherwise specified) the following, convenient for this study, system of symbols and units (Sze, 1981): gap E g and threshold ionization energy Е ion in eV; electric field E in V/cm; bias V b in V; multiplication factors α and β in cm -1 , electron charge q in C; dielectric constant of vacuum ε 0 in F/m; concentration including shallow donors N D and acceptors N A in cm -3 ; concentration gradient a in cm -4 ; width of SCR L р and L n in p and n layers and thicknesses of these layers (inset in Figure 3) in μm, light absorption coefficient γ in cm -1 . In this section, analytical dependences M (V ) in p − n structures have been calculated under no K (E ) = const condition.…”

“…Such calculations are possible because ratio K (E) − 1 lnK (E ) varies, typically, much slighter than E 7 . In some cases it allows using relation (45) to integrate analytically (in some cases -approximately) expressions (1) and (2) and, thus, get analytical, more or less universal, relatively simple dependences M (V ). The most typical cases are considered: abrupt (stepwise) and gradual (linear) p − n junctions like as in model given in (Sze, 1987), (Sze & Gibbons, 1966) and thin p + − n( p) − n + structure (like as p − i − n) with stepwise doping profile as in model presented in (Osipov & Kholodnov, 1987).…”

“…At this doping avalanche breakdown in Si occurs when electric field near insulator-semiconductor interface reaches value E BD ≅ 3 × 10 5 V/cm (Sections 3.1 and 3.2, (Sze, 1981), (Osipov & Kholodnov, 1987), (Sze & Gibbons, 1966)), and therefore К 0 ≅ 10 −2 (Sze, 1981), (Tsang, 1985), (Grekhov & Serezhkin, 1980), (Sze & Gibbons, 1966), (Stillman & Wolf, 1977), (Kuzmin et al, 1975). Measured in (Bogdanov et al, 1986) (Shotov, 1958) Finally, it is interesting to analyze application of expressions (45) and (76) to describe avalanche process in InSb. The fact is that dependence α(Е) in InSb was quite well known already in 1967 (Baertsch, 1967), but no one could obtain information about dependence β(Е) (Dmitriev et al, 1987), (Dmitriev et al, 1983), (Dmitriev et al, 1982), (Gavrjushko et al, 1968).…”