阅读说明：本技术 一种掺杂浓度可调的横向SiGe异质结双极晶体管 (Transverse SiGe heterojunction bipolar transistor with adjustable doping concentration ) 是由 金冬月 吴玲 张万荣 那伟聪 孙晟 杨绍萌 于 2019-08-23 设计创作，主要内容包括：本发明公开了一种掺杂浓度可调的横向SiGe异质结双极晶体管,为NPN型或PNP型横向SiGe HBT。通过在NPN型器件发射区和基区下方衬底电极加正电压(或在PNP型器件发射区和基区下方衬底电极加负电压),可有效增大发射区掺杂浓度并减小基区掺杂浓度,同时提高电流增益和特征频率；通过在NPN型器件集电区下方衬底电极加负电压(或在PNP型器件集电区下方衬底电极加正电压),可有效降低集电区掺杂浓度,提高击穿电压。与常规横向SiGe HBT相比,所述晶体管可通过改变位于发射区、基区和集电区下方衬底电极的外加电压来独立调节上述三个区的掺杂浓度,从而实现特征频率、电流增益和击穿电压的同步提高。(The invention discloses a lateral SiGe heterojunction bipolar transistor with adjustable doping concentration, which is an NPN type or PNP type lateral SiGe HBT. By applying positive voltage to the substrate electrode below the emitter region and the base region of the NPN type device (or applying negative voltage to the substrate electrode below the emitter region and the base region of the PNP type device), the doping concentration of the emitter region can be effectively increased, the doping concentration of the base region can be reduced, and the current gain and the characteristic frequency can be improved; by applying negative voltage to the substrate electrode below the collector region of the NPN type device (or applying positive voltage to the substrate electrode below the collector region of the PNP type device), the doping concentration of the collector region can be effectively reduced, and the breakdown voltage is improved. Compared with the conventional lateral SiGe HBT, the transistor can independently adjust the doping concentrations of the emitter region, the base region and the collector region by changing the external voltage of the substrate electrode below the three regions, thereby realizing the synchronous improvement of the characteristic frequency, the current gain and the breakdown voltage.)

1. A lateral SiGe heterojunction bipolar transistor with adjustable doping concentration is characterized in that:

the silicon-based epitaxial growth device comprises a Si substrate (20), a SiO ₂ buried oxide layer (21), a SiGe base region (22), a Si emitter region (23) and a Si collector region (24), wherein the SiGe base region (22), the Si emitter region (23) and the Si collector region (24) are located above a SiO ₂ buried oxide layer (21), a polysilicon layer (25) is located above the SiGe base region (22) and both sides of the polysilicon layer are in contact with a SiO ₂ layer (26), a base electrode (29) is located above the polysilicon layer (25), an emitter electrode (27) is located above a SiO ₂ buried oxide layer (21) and is in contact with the Si emitter region (23), a collector electrode (28) is located above a SiO ₂ buried oxide layer (21) and is in contact with the Si collector region (24), a substrate electrode (30) is located below the Si emitter region (23) and the SiGe base region (22) and is in contact with the Si substrate (20), and a substrate electrode (32) is located below the Si collector region (24) and is in contact with the Si base region (20), and the substrate electrode (32) is located between the SiO collector region (24) and the substrate (₂).

2. the lateral SiGe heterojunction bipolar transistor with adjustable doping concentration of claim 1, wherein:

the lateral SiGe heterojunction bipolar transistor is an NPN type lateral SiGe heterojunction bipolar transistor or a PNP type lateral SiGe heterojunction bipolar transistor; wherein for an NPN type lateral SiGe heterojunction bipolar transistor, the applied voltage at the substrate electrode (30) is between +3V and +5V, and the applied voltage at the substrate electrode (32) is between-0.5V and-1.5V; for a PNP type lateral SiGe heterojunction bipolar transistor, the applied voltage at the substrate electrode (30) is between-3V to-5V, and the applied voltage at the substrate electrode (32) is between +0.5V to + 1.5V.

3. the lateral SiGe heterojunction bipolar transistor with adjustable doping concentration of claim 1, wherein:

the thickness of the Si substrate (20) is between 20nm and 60nm, the thickness of the SiO ₂ buried oxide layer (21) is between 20nm and 50nm, the thicknesses of the Si emission region (23), the SiGe base region (22) and the Si collector region (24) are equal and are respectively between 20nm and 60nm, the widths of the Si emission region (23) and the Si collector region (24) are equal and are respectively between 30nm and 60nm, the width of the SiGe base region (22) is between 22nm and 60nm, and the thickness of the polysilicon layer (25) is between 5nm and 10nm and is between 18nm and 36 nm.

Technical Field

The invention relates to a transverse SiGe heterojunction bipolar transistor, in particular to a transverse SiGe heterojunction bipolar transistor with adjustable doping concentration, which is applied to the fields of high-speed memories, high-speed emitter coupled logic circuits, high-speed current type logic circuits and the like.

Background

The lateral SiGe Heterojunction Bipolar Transistor (HBT) adopting the silicon-on-insulator (SOI) technology not only has the advantages of small substrate parasitic capacitance, low leakage current, good high-frequency characteristics and the like, but also is compatible with the existing SOI CMOS process, and plays an increasingly important role in the field of microwave power.

Fig. 1 shows a schematic longitudinal cross-sectional view of a conventional lateral SiGe HBT using SOI technology, which is mainly composed of a Si substrate (10), a SiO ₂ buried oxide layer (11), a SiGe base region (12), a Si emitter region (13), and a Si collector region (14). for better compatibility with SOI CMOS processes, the device size of the conventional lateral SiGe HBT is typically on the order of nm.

Therefore, how to design a lateral SiGe HBT with adjustable doping concentration effectively overcomes the influence of semiconductor process deviation on the doping concentration levels of an emitter region, a base region and a collector region of a device, thereby realizing the simultaneous improvement of the characteristic frequency, the current gain and the breakdown voltage of the device, and having important theoretical and practical significance.

Disclosure of Invention

The invention discloses a lateral SiGe heterojunction bipolar transistor with adjustable doping concentration.

The invention relates to a transverse SiGe heterojunction bipolar transistor with adjustable doping concentration, which is characterized by comprising a Si substrate (20), a SiO ₂ buried oxide layer (21), a SiGe base region (22), a Si emitter region (23) and a Si collector region (24), wherein the SiGe base region (22), the Si emitter region (23) and the Si collector region (24) are all located above a SiO ₂ buried oxide layer (21), a polycrystalline silicon layer (25) is located right above the SiGe base region (22), and two sides of the polycrystalline silicon layer are all in contact with a SiO ₂ layer (26), a base electrode (29) is located right above the polycrystalline silicon layer (25), an emitter electrode (27) is located above a SiO ₂ buried oxide layer (21) and is in contact with the Si emitter region (23), a collector electrode (28) is located above the SiO ₂ buried oxide layer (21) and is in contact with the Si collector region (24), a substrate electrode (30) is located below the Si emitter region (23) and the SiGe base region (22) and is in contact with the Si base region (20), a substrate electrode (30) is located below the SiO collector region (32) and is located between the substrate (32) and the substrate (32).

The transistors include an NPN type lateral SiGe heterojunction bipolar transistor and a PNP type lateral SiGe heterojunction bipolar transistor. Wherein for an NPN type lateral SiGe heterojunction bipolar transistor, the applied voltage at the substrate electrode (30) is between +3V and +5V, and the applied voltage at the substrate electrode (32) is between-0.5V and-1.5V; for a PNP type lateral SiGe heterojunction bipolar transistor, the applied voltage at the substrate electrode (30) is between-3V to-5V, and the applied voltage at the substrate electrode (32) is between +0.5V to + 1.5V.

The thickness of the Si substrate (20) is between 20nm and 60nm, the thickness of the SiO ₂ buried oxide layer (21) is between 20nm and 50nm, the thicknesses of the Si emission region (23), the SiGe base region (22) and the Si collector region (24) are equal and are respectively between 20nm and 60nm, the widths of the Si emission region (23) and the Si collector region (24) are equal and are respectively between 30nm and 60nm, the width of the SiGe base region (22) is between 22nm and 60nm, and the thickness of the polysilicon layer (25) is between 5nm and 10nm and is between 18nm and 36 nm.

Compared with the conventional transverse SiGe HBT, the transistor can independently adjust the doping concentrations of the emitter region, the base region and the collector region of the device by changing the external voltages of the substrate electrodes positioned below the emitter region and the base region and the substrate electrodes positioned below the collector region, so that the characteristic frequency, the current gain and the breakdown voltage of the device are synchronously improved, and the microwave power working range of the transverse SiGe HBT is effectively expanded.

drawings

Further objects and advantages of the invention will be understood by reference to the following description taken in conjunction with the accompanying drawings. In these drawings:

FIG. 1 illustrates a schematic diagram of a longitudinal cross-section of a conventional lateral SiGe HBT;

FIG. 2 illustrates a schematic longitudinal cross-sectional view of an embodiment of the present invention;

FIG. 3 illustrates a two-dimensional plot of electron concentration distribution for a conventional lateral SiGe HBT emitter region;

FIG. 4 illustrates a two-dimensional plot of electron concentration distribution for an emission region of an embodiment of the present invention;

FIG. 5 illustrates the improvement in device current gain by embodiments of the present invention;

FIG. 6 illustrates a two-dimensional plot of hole concentration distribution for a conventional lateral SiGe HBT base region;

FIG. 7 illustrates a two-dimensional plot of base region hole concentration distribution for an embodiment of the present invention;

FIG. 8 illustrates the improvement of device eigenfrequency by embodiments of the present invention;

FIG. 9 illustrates a two-dimensional plot of electron concentration distribution for a conventional lateral SiGe HBT collector region;

FIG. 10 illustrates a two-dimensional plot of collector region electron concentration distribution for an embodiment of the present invention;

Fig. 11 illustrates the improvement of the device breakdown voltage BV _CBO by the embodiment of the present invention.

Detailed Description

The embodiment of the invention specifically expresses the content of the invention by taking an NPN type transverse SiGe HBT as an example. The field to which the invention relates is not limited thereto.