Visual Photonics Epitaxy Co., Ltd.

Min-Nan Tseng

Yu-Chung Chin

Chao-Hsing Huang

Kai-Yu Chen

Kun-Chuan Lin

Huai-Tung Yang

Shih-Jane Tsai

Provided is a high ruggedness HBT, including a first emitter cap layer and a second emitter cap layer formed between an emitter layer and an ohmic contact layer, or only an emitter cap layer is formed between them. When the first and second emitter cap layers are provided, bandgaps of the first or second emitter cap layer are changed, and the ruggedness of the HBT is improved. When an emitter cap layer is provided, an electron affinity of at least a portion of the emitter cap layer is less than or approximately equal to an electron affinity of the emitter layer, and the ruggedness of the HBT is improved.

High ruggedness heterojunction bipolar transistor

The disclosure provides a high ruggedness HBT structure, including: a sub-collector layer on a substrate and formed of an N-type III-V semiconductor material; a collector layer on the sub-collector layer and formed of a III-V semiconductor material; a base layer on the collector layer and formed of a P-type III-V semiconductor material; an emitter layer on the base layer and formed of one of N-type semiconductor materials of InGaP, InGaAsP and InAlGaP; a first emitter cap layer on the emitter layer and formed of one of undoped or N-type semiconductor materials of AlGaAs, AlGaAsN, AlGaAsP, AlGaAsSb, and InAlGaAs, x having a highest value between 0.05&#x2264;x&#x2264;0.4, and y, z, r, w&#x2264;0.1; a second emitter cap layer on the first emitter cap layer and formed of an N-type III-V semiconductor material; and an ohmic contact layer on the second emitter cap layer and formed of an N-type III-V semiconductor material.

High ruggedness heterojunction bipolar transistor structure

Provided is a heterojunction bipolar transistor (HBT) structure with a bandgap graded hole barrier layer, including: a sub-collector layer including an N-type group III-V semiconductor on a substrate, a collector layer on the sub-collector layer and including a group III-V semiconductor, a hole barrier layer on the collector layer, a base layer on the hole barrier layer and including a P-type group III-V semiconductor, an emitter layer on the base layer and including an N-type group III-V semiconductor, an emitter cap layer on the emitter layer and including an N-type group III-V semiconductor, and an ohmic contact layer on the emitter cap layer and including an N-type group III-V semiconductor. Bandgaps of the hole barrier layer at least include a gradually increasing bandgap from the base layer towards the collector layer and a largest bandgap of the hole barrier layer is greater than bandgap of the base layer.

Heterojunction bipolar transistor structure with a bandgap graded hole barrier layer

The disclosure provides an HBT structure with bandgap graded hole barrier layer, comprising: a sub-collector layer, a collector layer, a hole barrier layer, a base layer, an emitter layer, an emitter cap layer, and an ohmic contact layer, all stacked sequentially on a substrate; with the hole barrier layer formed of at least one of AlGaAs, AlGaAsN, AlGaAsP, AlGaAsSb, and InAlGaAs, Aluminum composition being less than 22%, and In, N, P, and Sb compositions being respectively less than or equal to 10%; wherein bandgaps of the hole barrier layer at least comprise a gradually increasing bandgap from the base layer towards the collector layer and the largest bandgap of the hole barrier layer is greater than bandgaps of the base layer and the collector layer.

A directed epitaxial heterojunction bipolar transistor (HBT) structure is directly or indirectly formed on a GaAs substrate that is formed by a (100) face towards a (111)B face with an angle of inclination between 0.6&#xb0; and 25&#xb0;, and includes a sub-collector layer, a collector, a base layer, an emitter layer, an emitter cap layer and an ohmic contact layer, which are sequentially formed on the substrate. A tunnel collector layer formed by InGaP or InGaAsP is provided between the collector layer and the base layer. Since an epitaxial process is performed on the substrate from a (100) face towards a (111)B face with an angle of inclination between 0.6&#xb0; and 25&#xb0;, indium and gallium contained in InGaP or InGaAsP are affected by the ordering effect such that InGaP or InGaAsP used in the emitter layer and/or the tunnel collector layer has a higher electron affinity or a smaller bandgap.

Directed epitaxial heterojunction bipolar transistor

A material made by arranging layers of gallium-arsenide-antimonide (GaAsSb, 0.0&#x2266;x&#x2266;1.0) and/or indium-gallium-arsenic-nitride (InGaAsN, 0.0&#x2266;y, z&#x2266;1.0) in a specific order is used to form the transistor base of a heterojunction bipolar transistor. By controlling the compositions of the materials indium-gallium-arsenic-nitride and gallium-arsenide-antimonide, and by changing the thickness and order of the layers, the new material would possess a specific energy gap, which in turn determines the base-emitter turn-on voltage of the heterojunction bipolar transistor.

Growing community of inventors

Taipei, Taiwan

Min-Nan Tseng