Heterojunction bipolar transistor structure with high current gain and processing method thereof

Abstract

The invention discloses a heterojunction bipolar transistor improved structure with high current gain and a processing method of the heterojunction bipolar transistor improved structure. The improved structure comprises a substrate, a p type doped buffer layer, a primary collector layer, a collector layer, a base layer, an emitter layer, an emitter covering later and an emitter contact layer. A base electrode contact area is etched though multi-channel etching processing, the etching processing is stopped on the base layer, a collector electrode contact area is etched in the base electrode contact area, and the etching processing is stopped on a secondary collector layer. In the base electrode contact area, a base electrode is arranged on the base layer. A collector electrode is arranged in the collector electrode contact area and on the collector layer. An emitter electrode is then arranged on the emitter layer.

Description

Technical field [0001] The invention relates to an improved structure of a heterojunction bipolar transistor and its processing method, in particular to a p-type doped buffer layer between the collector layer and the substrate of the heterojunction bipolar transistor, Improved structure and processing method of heterojunction bipolar transistor capable of achieving high current gain properties. Background technique [0002] High current gain Heterojunction Bipolar Transistor (HBT) has the advantages of high efficiency, high linearity, high power density and small area. It is often used in wireless communications as a microwave power amplifier, which is very important in the communications electronics market. One of the important components. [0003] figure 1 It is a schematic cross-sectional view of the epitaxial layer structure of a conventional heterojunction bipolar transistor. The epitaxial layer structure is formed on a substrate 101 and includes a primary collector layer 10...

AI Technical Summary

Problems solved by technology

In general, in order to improve the device characteristics of the transistor, the resistivity of the collector electrode 119 must be reduced, usually by increasing the n-type doping concentration of the sub-collector layer 107 (usually the doping impurity is silicon Si), but As the doping concentration increases, the epitaxial defect density of the sub-collector layer 107 also increases, resulting in a decrease in current gain.

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