RU533157C - Method of producing silicon multi-emitter transistors - Google Patents

Description

The invention relates to electronic technology for the manufacture of semiconductor devices, in particular silicon transistors and microwave power transistors with nichrome film resistors.

There is a known method of manufacturing silicon multi-emitter transistors with nichrome film resistors, in which aluminum metallization is used to form contacts to the active areas of the transistor and film resistors. ,

However, aluminum metallization in microwave transistors has a number of disadvantages, in particular electromigration at high current densities.

Therefore, in recent years, multilayer gold-containing metallization has been increasingly used in microwave transistors, which has increased resistance to electromigration. In another known method for manufacturing silicon multi-emitter transistors, active regions of transistors are formed, nichrome is applied, nichrome resistors are formed, a gold-containing multilayer coating is applied, contacts to the active regions of transistors and resistors are formed using ion-chemical etching. The gold-containing coating in this method consists of titanium-tungsten-gold. Gold is a required component of such metallization and constitutes its upper LAYER (main current-carrying layer). Tungsten in this case prevents the reaction between gold and titanium applied to provide ohmic contact.

However, there are serious difficulties in obtaining the desired multilayer metallization pattern by chemical etching, because it is practically impossible to obtain the required dimensions of the metallization comb structure (2-3 microns) using chemical etchants. Therefore, ion-chemical etching is used to obtain a multilayer metallization pattern.

The purpose of the invention is to increase the reliability of transistors.

The goal is achieved in that before applying the multilayer gold-containing metallization on the surface of nichrome create a layer of aluminum with a thickness of 0.1-0.2 microns, and after the formation of contacts aluminum that is not coated with multilayer metallization is removed.

The fabrication of multi-emitter silicon transistors by nichrome resistors is carried out in the following order.

After the active regions of the transistor structure are formed, a nichrome layer is applied to the surface of the structure, and an aluminum layer 0.1-0.2 microns thick is applied over it. Next, photolithographic formation of resistors is carried out.

Next-step sequentially

The layers of multilayer gold-containing metallization are sprayed, and then photo-engraving of the metal contacts is carried out by ion-chemical etching. The latter has very little effect on aluminum, which thus reliably protects nichrome resistors. At the end of the ion-chemical etching, the aluminum layer is removed in the chemical etchant.

0 In practice, the manufacture of multi-emitter microwave transistors with nichrome resistors is shown in the following example.

1.In the initial silicon wafers with an epitaxial layer

Ap12KEF2.01v

  250 ECES 0.1 -7 (111) form the base and emitter layers.

2. At the UVN-75R-1 installation they sprayed at 0 °

one cycle of nichrome 400-700 A thick and aluminum 0.1-0.2 microns thick.

Nichrome is sprayed with the ion-plasma method, aluminum-electron-beam method 5.

Nichrome spraying mode: P 6-10 mm Hg;

 mA

Mp 180-220 ° C; 0 Rs fO-20 Ohm / kVDrat

Aluminum spraying mode: -10 mmHg:

5kV. mA:

t 15c: Tn 250 ° C: 5, 1-0.2 μm.

3. Photolithographic techniques form the pattern of resistors,

4. Photo engraving open contact windows.

0 5. Multilayer metallization is sprayed using the RF diode sputtering method on an installation equipped with a set of targets:

The first layer (titanium): 10 mm Hg .; 5, 05-0.1 microns;

Mp 200 ° C

The second layer (tungsten) 10 mm Hg:

, 1-0.2 microns:

Claims (1)

Mp 230 ° C Third layer (gold) mm Hg; 9-1.1 microns; Mp 250 ° C 6. The photoresist is applied by centrifugation and a metallization pattern is created. 7. Etching of the multilayer metallization by the ion-chemical method in a mixture of freon and oxygen is carried out. Duration of etching is 2-3 hours. 8. Aluminum poison agent is removed with the composition: 35 ml of HNO3, 75 ml of HzRO / i, 15 ml of CH3COOH and 5 ml of H20 Etching time 10-15 minutes. SUMMARY OF THE INVENTION METHOD FOR PRODUCING SILICON MULTI-EMITTER TRANSISTORS, comprising forming active regions of transistors, applying nichrome, forming resistors and applying a multilayer gold-containing coating, forming contacts to active regions of transistors and resistors using ion-chemically one metal etching does not act . At the same time, during ion-chemical etching, there is absolutely no etching of nichrome resistors. Therefore, the values of the resistors do not deviate from the set ones, and therefore the parameters of the microwave transistors are precisely maintained. (56) Electronics, No. 19, M .: Mir, 1971. p. 58. Electronics. No. b, M .: Mir, 1975, p. 23. etching, characterized in that, in order to increase the reliability of the transistors, before applying a multilayer gold-containing coating on the surface of the nichrome, an aluminum layer 0.1-0.2 microns thick is created, and after the formation of the contacts, aluminum. not coated with multilayer metallization, removed.