Analysis of the Kirk Effect in Silicon-Based Bipolar Transistors With a Nonuniform Collector Profile

Abstract

In this paper, the Kirk effect has been analyzed for silicon-based bipolar transistors (BJTs) with a nonuniform collector profile. We show that, for any arbitrary collector doping profile, the Kirk effect starts when the electron concentration equals the average doping concentration in the depletion region. We present a basic guideline for determining the collector current density at the onset of Kirk effect ( ) for any collector doping profile and simple expressions for and the electrical field in the collector drift region for the case of a linearly graded collector drift region. These analytical expressions are verified with device simulations. The Kirk effect for this kind of transistor is substantially different from that presented previously for transistors having a uniform collector drift region. For example, the possibility of the onset of the Kirk effect in a partially depleted collector occurs, while in a uniform collector profile the effect can only occur in a fully depleted collector. Our expressions can be used to do approximate analytical calculations for optimizing future BJTs.

Characteristics of Lateral Diffused Metal–Oxide–Semiconductor Transistors with Lightly Doped Drain Implantation through Gradual Screen Oxide

“…In this work, a gradual junction profile formed by selfalignment implant through gradual screen oxide in HV lateral diffused metal-oxide-semiconductor (LDMOS) transistors is proposed to improve off-state V BD without sacrificing device drivability. Experimental data of improved V BD , less severe in Kirk effect, [14][15][16][17][18][19][20] and hot-carrier induced device degradation under various stress conditions are presented and discussed. Technology computer aided design (TCAD) simulations are performed results of electric field and impact ionization (I-I) rate are analyzed to explain the experimental data.…”

EnhancedfTand linearity performance of InGaP/GaAs HBTs using a non-uniform doping collector

“…The output power is primarily limited by both breakdown voltage and current handling capability in GaAs HBTs [7]. The current handling capability and operation frequency of HBT are limited by Kirk effect [8][9][10]. Device current gain and cutoff frequency (f T ) decrease significantly at the onset of Kirk effect.…”

Field-plate assisted RESURF power devices : gradient based optimalization, degradation and analysis

“…Commonly referred to as the base push out or Kirk effect [42], [43] this effect causes a destructive snapback phenomenon [44], limits the voltage handling capabilities (or Safe-Operating-Area, SOA) of RESURF devices [45] and makes finding both the physical and electrical HCI points of interests yet more complicated [46]. Furthermore accelerated lifetime tests of HV-devices often result in self-heating effects which are otherwise not present in normal device operation [47].…”

“…1.8b) a constant mobile charge increase due to on-state operation will not affect this optimal gradient. The additional constant mobile charge will only shift the zero charge point (n − = N D (x) + ) away from the (x = 0) p-body/n-drift junction into the drift extension [43].…”

“…Although this work focused on diodes and (N)MOS transistors, gradient based optimization has also been reported in other types of devices for various applications such as (RF) bipolar transistors to improve the tradeoff between the cutoff frequency and off-state breakdown voltage [43,113] but also in alternative power devices such as IGBTs [66] and thyristors [114] to name a few. Another example that should be mentioned is the variable capacitor.…”