JPH05326545A - Selective crystal growth method and manufacture of semiconductor device using the same - Google Patents

Abstract

PURPOSE:To obtain the title method and the manufacturing method wherein carbon-doped gallium arsenide can be obtained by a lower temperature selective growth technique, and a high yield manufacturing process can be realized without decreasing the quality of a semiconductor device. CONSTITUTION:Trimethylgallium(TMG) and tridimethylaminoarsenic ((Ch3)2N)3 As) are used as row material. The title device is an AlGaAs/GaAs based hetero junction bipolar transistor having a carbon-doped P-type GaAs outer base layer 6 which is selectively regrown on a cabon-doped P-type GaAs base layer 3, by MOMBE or the like at about 400 deg.C and 10<-2>-10<-3>Torr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a selective crystal growth method for selectively epitaxially growing a carbon-doped gallium arsenide crystal as a type electrode layer and the like, and a method for manufacturing a semiconductor device using the same.

[0002]

2. Description of the Related Art In recent years, A having a laminated structure of semiconductor thin films
Since the crystal growth of the 1GaAs / GaAs heterojunction bipolar transistor (HBT) is facilitated, research and development aiming at practical use are being actively conducted.

The most difficult point in manufacturing a device is that the thickness is 0.
Exactly expose the base layer of about 8 μm and contact the base metal. It is no exaggeration to say that the device yield is determined by this process. To solve this difficulty,
External base region (electrode layer) by selective regrowth method
A method of forming the is proposed. In this case, it should be noted that the thermal history during regrowth should not change the existing epitaxial structure. Therefore, it is necessary to regrow at the lowest temperature possible. Previously proposed regrowth methods MBE, MOCVD or MOMBE
Is not sufficient from the viewpoint of selectivity in the low temperature region.
Above all, MOMB using TMG and arsenic (solid)
The E method (Shimanawaki et al. IEICE Technical Committee on Electronic Devices (January 1991)) is superior to the other two methods in that carbon-doped p-type GaAs electrode layers can be selectively grown at a low temperature of 450 ° C. Are better.

[0004]

However, even at this temperature, it is not sufficient to manufacture an AlGaAs / GaAs system HBT. This is because the carrier concentration of Si-doped InGaAs grown at a low temperature decreases at around 500 ° C., which may cause an increase in emitter resistance and deterioration in high frequency characteristics. Therefore, further development of low-temperature selective growth technology has been desired.

The present invention has been made in view of the above circumstances, and a carbon-doped gallium arsenide crystal can be obtained by a further low-temperature selective growth technique, and a high-yield manufacturing process without deteriorating the performance of a semiconductor device. It is an object of the present invention to provide a selective crystal growth method that can be realized and a semiconductor device manufacturing method using the same.

[0006]

In order to solve the above-mentioned problems, the present invention uses carbon-doped gallium arsenide crystal using trimethylgallium (TMG) and tridimethylaminoarsenic (((Ch ₃ ) ₂ N) ₃ As) as raw materials. And a selective crystal growth method for forming a regrowth external base region of a heterojunction bipolar transistor by the selective crystal growth method. Is the way.

[0007]

The present invention is based on trimethylgallium (TMG) and tridimethylaminoarsenic (((Ch ₃ ) ₂ N) ₃ A.
By using s) as a raw material, carbon-doped GaA can be obtained at a low temperature.
s can be selectively epitaxially grown. AlGaA with extrinsic base region formed by this method
The s / GaAs-based heterojunction bipolar transistor is
It gives good high-frequency characteristics without the problem of increased emitter resistance. In addition, the device yield is dramatically improved.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an AlGaA according to an embodiment of the present invention.
It is a sectional view showing an s / GaAs system heterojunction bipolar transistor. That is, on the semi-insulating GaAs substrate 12, an n-type GaAs collector buffer layer 1, a GaAs collector layer 2, a carbon-doped p-type GaAs base layer 3, and an n-type A.
l _0.3 Ga _0.7 As emitter layer 4 and n-type InGaAs emitter cap layer 5 are sequentially epitaxially grown. Next, this is processed into a mesa type, and trimethylgallium (TM
G) and tridimethylaminoarsenic (((Ch ₃ )
₂ N) ₃ As) as a raw material, and the carbon-doped p-type GaA
s About 400 ° C. on the base layer 3 by MOMBE, etc., 1
After the carbon-doped p-type GaAs external base layer 6 selectively regrown at 0 ⁻² to 10 ⁻³ Torr is formed, an emitter electrode (WSi / W) 7, a base electrode (Ti / W) 8, a collector electrode ( AuGe / Ni) 9 is formed. After that, the insulating film 11 is formed. Reference numeral 10 is an element isolation layer (ion implantation insulation layer). The order of the manufacturing steps may be changed as appropriate.

The key to the realization of selective growth at low temperature is (1) to minimize the formation of growth nuclei on a mask where crystal growth is not desired, and (2) to promote rapid crystal growth on the GaAs surface. is there. Therefore, it is better to use the organometallic compound gas raw material as the raw material, rather than the metal solid raw material that tends to adhere to the mask surface. This is no exception to arsenic, which has a high vapor pressure. Therefore, the Ga raw material also serves as a p-type impurity carbon raw material, and is trimethylgallium (TMG).
And Metallic arsenic is excluded from the As raw material for the above reasons, and arsine, which is usually used in the MOCVD method, has a high decomposition temperature and is not suitable. Tridimethylaminoarsenic (((Ch ₃ ) ₂ N) ₃ As) is adopted from the viewpoint of lower decomposition temperature than arsine.

The vapor pressure of (Me ₂ N) ₃ As is as follows.

Log P (Torr) = 8.289-2391 / T (K) mp. -53 ° C, bp. 170 ° C

[0013]

As described above, according to the present invention, trimethylgallium (TMG) and tridimethylaminoarsenic (((Ch ₃ ) ₂ N) ₃ As) are used as raw materials, so that carbon-doped GaAs can be obtained at a low temperature. Can be selectively grown epitaxially. The AlGaAs / GaAs heterojunction bipolar transistor having the external base region formed by this method gives good high frequency characteristics without the problem of increase in emitter resistance. In addition, the device yield is dramatically improved.

[Brief description of drawings]

FIG. 1 is an AlGaAs / GaA according to an embodiment of the present invention.
It is sectional drawing which shows an s-system heterojunction bipolar transistor.

[Explanation of symbols]

1 ... n-type GaAs collector buffer layer, 2 ... GaAs collector layer, 3 ... carbon-doped p-type GaAs base layer, 4 ...
n-type Al _0.3 Ga _0.7 As emitter layer, 5 ... n-type InG
aAs emitter cap layer, 6 ... Selectively regrown carbon-doped p-type GaAs external base layer, 7 ... Emitter electrode (WSi
/ W), 8 ... Base electrode (Ti / W), 9 ... Collector electrode (AuGe / Ni), 10 ... Element isolation layer (ion implantation insulating layer), 11 ... Insulating film, 12 ... Semi-insulating GaAs
substrate.

Claims (2)

[Claims] 1. A trimethyl gallium (TMG) and tri dimethylamino arsenic _{(((Ch 3) 2 N} ) 3 As) selectively selective crystal growth, which comprises epitaxially growing a carbon-doped gallium arsenide crystal as a raw material Method. 2. A method of manufacturing a semiconductor device, wherein the regrown extrinsic base region of a heterojunction bipolar transistor is formed by the method according to claim 1.