CS267561B1 - Multistage transistor of darlingtom type with high resistance to second breakdown - Google Patents

Abstract

The drawback is eliminated existing multistage designs transistors and achieve favorable results reldce between transistor resistance second breakdown and current amplifier for short. This purpose is achieved by construction Darlington Multistage Transistor where the thickness of the base layer semiconductor material in space below the structured emitter layer the last degree is the least 10% than the base layer thickness semiconductor material in space below the split first emitter layer degree.

Description

high resistance against a second orifice (57) rim _Océ solution is to eliminate the disadvantages of previous constructions of multi-stage transistors and achieve přiznivějěi session between the resistance of transistor against breakdown, and a second current amplification factor h _{£ 21} short.

This object is achieved by designing a multi-stage Darlington transistor wherein the layer thickness of the base semiconductor material in the space below the segmented emitter layer of the last stage is at least 10% more than the layer thickness of the base semiconductor material in the space below the segmented first stage emitter layer.

CS 267561 Bl

CS 267 561 81

BACKGROUND OF THE INVENTION The present invention relates to a multistage transistor of the type Derlington β of high second-breakdown resistance and with a high current gain factor h h.

Known types of multistage Darlington transistors have the same layer thickness of the basic semiconductor material at all stages. This results in low resistance to second breakdown in the construction of Darlington multistage transistors with a high current boost factor h _21E . In the construction of β with a low current amplification factor h ^ _{lE, the} disadvantage of the increased power requirements of the control sources.

These disadvantages are overcome by the Darlington multistage transistor having a high second breakdown resistance according to the invention. The thickness of the layer of the basic semiconductor material in the space below the segmented emitter layer of the last stage J is at least 10% greater than the thickness of the layer of the basic semiconductor material in the space below the segmented emitter layer of the first stage.

The advantage of this design is that, compared to the known types of Darlington multistage transistors, there is a more favorable relation between the transistor resistance to second breakdown, possibly between the voltage U _r U - »and the short-circuit current amplification factor h '.

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The attached drawing shows the structure of a two-stage transistor in Darlington circuit in partial section.

The Darlington two-stage transistor consists of layers 11 and 21 of basic semiconductor material, outer highly doped layers 12 and 22, base gates 13 and 23, base contacts 14 and 24, segmented emitter layers 15 and 25, and emitter contacts 16 and 26.

In the region of the first stage 10, a portion of the base layer 11 is etched from the same side of the semiconductor plate before forming the concentration profile of the base layer 13, so that after formation of the base layer 13 and the emitter layer 15 the thickness is below the segmented emitter layer 15 a layer 11 of the basic semiconductor material 65jro.

In the region of the second stage 20, the thickness of the base semiconductor material layer 21 below the segmented emitter layer 25 is 80 µm.

Reduced layer thickness of the semiconductor materiel ll basic first stage 10 provides an improvement value of the tripping time t _Q FF, the current amplification factor h _{2 E-permeable} properties and short multi-stage transistor, wherein no reduction values Please type second breakdown which is determined by the characteristics of the second stage 20th

Multistage Transistor Design According to the Invention It is suitable for high voltage power transistors designed to operate in an inductive load epinecira mode.

Claims (1)

Object of the invention Multistage Darlington transistor with high second breakdown resistance, containing! structures of two or more stages, each stage comprising a layer of base semiconductor material adjoined on one side by an outer highly doped layer of the same type of electrical conductivity as the base semiconductor material layer and on the other side by a base layer of opposite electrical conductivity layer the base layer is provided on the outside of the surface with a base contact and a segmented emitter layer provided with an emitter contact, while the outer high-doped layer is provided with a contact connected to the first main electrode of the multistage transistor; the base of the next stage, then the emitter contact of the last stage is connected to the second main electrode of the multistage transistor and the base contact of the first stage is connected to the third stage a main electrode of a multistage transistor, characterized in that the thickness of the layer (21) of the basic semiconductor material in the space below the segmented eroitor layer (25) of the last stage (20) is at least 10% more than the thickness of the layer (11) a first stage (10) emitter layer (15). 1 drawing • ’Ί CS 267 561 Bl