JPS63144567A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a semiconductor device having excellent characteristics through a simple manufacturing technique using no epitaxial technique by forming an insulating film for isolating elements to a first conductivity type semiconductor base body and selectively shaping a second conductivity type buried layer by employing an ion implantation method. CONSTITUTION:An oxide film 22 for isolating elements is formed to a substrate 21. An oxide film is 200Angstrom is shaped in an element region, and phosphorus ions are implanted selectively at acceleration voltage of 1.0-2MeV and in dosage of 1X10<15>-1X10<16>cm<-2> through a photoetching method, thus shaping a buried layer 23. Said oxide film is peeled selectively through the photoetching method, and phosphorus ions are implanted under conditions of 100KeV and 1X10<12>cm<-2>, thus forming a collector 24. Likewise, a base 25 by boron under conditions of 20KeV and 1X10<14>cm<-2> and an external collector 26 by phosphorus under conditions of 100KeV and 5X10<15>cm<-2> are formed through ion implantation by employing the photoetching method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a semiconductor device, and is particularly used for a method for connecting bipolar semiconductor devices.

(Prior Art) A conventional method for manufacturing an NPN bipolar transistor will be explained with reference to FIG. First, a heavily doped N-type buried layer 3 is formed on a P-type (100) substrate 1 by diffusion of antimony, etc., a P-type epitaxial layer 2 with a thickness of approximately 2 μm is formed, and an N-type well layer 4 is formed using a normal method. Form. (Second
Figure (a)) Next, 5,000 oxide films 12 are formed in the non-device region using selective oxidation, etc., an oxide film 5 is formed in the device region, and a P-type base layer is selectively formed by ion implantation. form 6. (FIG. 2(b)) Further, a part of the oxide film 5 is opened, a polycrystalline silicon layer 7 is formed on the entire surface, and N such as arsenic is formed.
Type impurities are introduced by ion implantation or the like, and heat treatment is performed to form an N-type emitter layer 8. (FIG. 2(C)) The polycrystalline silicon layer 7 is partially etched by photolithography using the photoresist 9 as a mask, and ions are implanted using the photoresist 9 and the oxide film 12 as a mask. A highly doped P-type external base layer 10 is formed by a method or the like. Second
(d) Further, an N-type high concentration external collector layer 11 is formed by diffusion, ion implantation, or the like. (FIG. 2(e)) Furthermore, a wiring layer is formed by a normal method.

(Problems to be Solved by the Invention) However, the conventional method has the following drawbacks.

(1) Since epitaxial growth technology is used, antimony is usually used as an N-type impurity for the buried layer in order to suppress the autodoping effect. However, since antimony has low solid solubility in silicon,
In order to realize a low resistance buried layer, it is necessary to form a deep antimony layer.

(distance from the silicon surface to the surface of the buried layer) cannot be formed with good controllability.

(2) High temperature (usually 1100℃) for epitaxial layer formation
℃ or higher), the antimony layer diffuses into the epitaxial layer, and the effective epitaxial deashing becomes thinner, making it difficult to form a thin epitaxial layer with good controllability, resulting in poor controllability of bipolar transistor characteristics. .

(3) Since the epitaxial layer has a higher defect density than a normal silicon substrate, semiconductors manufactured using epitaxial technology have many defective products and are expensive.

The present invention has been made in view of these circumstances, and provides a method for manufacturing a semiconductor device that can realize a simple manufacturing technique that does not use epitaxial technology and has excellent characteristics.゛ [Structure of the Invention] (Means for Solving the Problems) In manufacturing a semiconductor device including a bipolar transistor, the present invention provides that after forming an element isolation insulating film on a first conductivity type semiconductor substrate, ions are removed. This is a method of manufacturing a semiconductor device, comprising a step of selectively forming a second conductivity type buried layer using an injection method. That is, when forming a high concentration buried layer, unlike the conventional formation of a buried layer by diffusion and subsequent formation of a silicon substrate by epitaxial technology, the buried layer is formed by performing high acceleration ion implantation into a normal single crystal silicon substrate, Its feature is that it has an effect equivalent to or better than that of conventional buried layer/epitaxial growth.

(Example) An example of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing the process of the same embodiment. First, P type (
100) Form an oxide film 22 with a thickness of 500 OA on a silicon substrate 21 using a commonly used method. (Figure 1 (
a)) Next, a 200-layer oxide film is formed on the device region, and 1.
Accelerating voltage of 0-2 MeV, dose EtlxlO” ~1
A buried layer 23 is formed by selectively ion-implanting phosphorus at xlO" cm-2 using a photolithography method (see Fig. 1).
b)) Although the ion implantation conditions for forming the buried layer 23 are different under other manufacturing conditions, the optimum conditions in this example are 1.5 MV.
, lXl0α-2 to form the collector 24. Furthermore, using the same photo-etching method, 2 boron
Base 25, phosphorus at 100KeV, 5X10” cry°2 under the conditions of 0KeV, I x 10”ax-2
The external collector 26 is formed by ion implantation under the following conditions. (
(FIG. 1C) Next, an emitter and an external base are formed in the same manner as in the conventional embodiment, and then wiring is performed.

In this embodiment, the buried layer is made of phosphorus, but even if arsenic is used, the effect remains the same if the ion implantation accelerating voltage is adjusted to have the same projected range as phosphorus.

Furthermore, although this embodiment describes the method of manufacturing only a bipolar element, a bipolar CMO3IU composite element, so-called B1-C
A similar method can also be applied to the manufacture of MOS devices.

According to the above embodiments: (1) Since epitaxial technology is not used, a semiconductor device can be provided at low cost and with fewer defective products.

(2) During the formation of the buried layer, the thermal process after formation can be minimized because an epitaxial layer and antimony are not used as in the conventional method, and controllability is improved, resulting in high performance characteristics.

(3) For the same reason as (2), there is little lateral diffusion of the buried layer, and high integration is possible.

The buried layer 23 is shallower than the others, and there is no need to form a deep external collector, so the thermal process can be reduced and high performance characteristics can be obtained.

[Effects of the Invention] As described above, according to the present invention, a simple manufacturing technique that does not use conventional epitaxial technology can be realized, and a semiconductor device with excellent characteristics can be provided.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram of an embodiment of the present invention, and FIG. 2 is a process explanatory diagram of a conventional apparatus. 21... P-type silicon substrate, 22... Oxide film, 23
...N-type buried layer, 24...Collector, 25...
- Base, 26...external collector.

Claims (3)

[Claims] (1) When manufacturing a semiconductor device including a bipolar transistor, after forming an element isolation insulating film on a first conductivity type semiconductor substrate, a second conductivity type semiconductor substrate is selectively formed using an ion implantation method.
1. A method of manufacturing a semiconductor device, comprising a step of forming a conductive buried layer. (2) The method for manufacturing a semiconductor device according to claim 1, wherein the buried layer is made of phosphorus or arsenic. (3) The phosphorus has an acceleration voltage of 1 to 2 MeV and a dose of 1×
Claim 2, characterized in that the ions are implanted under the conditions of 10^1^5 to 1 x 10^1^6 cm^-^2.
A method for manufacturing a semiconductor device according to section 1.