CN103094117A

CN103094117A - Technique method of manufacturing bottom thick grate oxide layer groove metal oxide semiconductor (MOS)

Info

Publication number: CN103094117A
Application number: CN2011103404982A
Authority: CN
Inventors: 金勤海; 沈浩峰; 袁秉荣
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2011-11-01
Filing date: 2011-11-01
Publication date: 2013-05-08
Anticipated expiration: 2031-11-01
Also published as: CN103094117B

Abstract

The invention discloses a technique method of manufacturing a bottom thick grate oxide layer groove metal oxide semiconductor (MOS). The technique method of manufacturing the bottom thick grate oxide layer groove MOS comprises the following steps. The first step is that an epitaxial layer grows on a heavily-doped silicon substrate, and a first lightly-doped epitaxial layer is formed; the second step is that silicon dioxide grows on the first lightly-doped epitaxial layer; the third step is that a photoresist pattern is formed; the fourth step that the silicon dioxide which is unblocked by photoresist is etched cleanly, so that the first lightly-doped epitaxial layer except the photoresist is exposed, and then the photoresist is eliminated; the fifth step is that a second epitaxial layer grows selectively; the sixth step is the silicon dioxide is etched backward to required thickness through wet process or dry process etching technology, and a groove and a thick grate oxide layer at the bottom of the groove are formed. According to the technique method of manufacturing the bottom thick grate oxide layer groove MOS, selectively epitaxial growth is adopted to form the groove, the oxide layer inside the groove is etched backward to the required thickness so as to serve as the thick grate oxide layer at the bottom of the groove. According to the technique method of manufacturing the bottom thick grate oxide layer groove MOS, the structure of the bottom thick grate oxide layer groove MOS is enabled to be easily formed and controlled.

Description

Make the process of bottom thick grating oxide layer groove MOS

Technical field

The present invention relates to a kind of manufacture method of semiconductor device, be specifically related to a kind of process of making bottom thick grating oxide layer groove MOS.

Background technology

Bottom thick grating oxide layer (thickness is 500～10000 dusts) MOS (metal-oxide semiconductor (MOS)) can make that between the device grid leak, electric capacity reduces greatly.Existing technique forms groove by etching, but this method makes the formation of bottom thick grating oxide layer very difficult.And existing technique generally only has one deck extension in heavy doping, and when needs have two-layer outer time-delay, prior art processes is controlled accurate not to the relative position of extension and groove, therefore makes the Comparision difficulty of optimizing epi dopant and device performance.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of process of making bottom thick grating oxide layer groove MOS, and it can easily be realized and control so that the formation of the bottom thick grating oxide layer of groove MOS becomes.

For solving the problems of the technologies described above, the technical solution that the present invention makes the process of bottom thick grating oxide layer groove MOS is to comprise the following steps:

The first step at heavily doped silicon Grown epitaxial loayer, forms the first light dope epitaxial loayer;

Second step, the silicon dioxide of growing on the first light dope epitaxial loayer;

The thickness of formed silicon dioxide is equal to, or greater than the follow-up gash depth that will form.

The 3rd step, adopt photoetching process, gluing, photoetching on silicon dioxide form photoetching offset plate figure;

The 4th step, etching, the silicon dioxide etching of not blocked by photoresist is clean, expose the first light dope epitaxial loayer beyond photoresist; Then remove photoresist;

The 5th step, selective growth the second epitaxial loayer; Superficial growth the second light dope epitaxial loayer at the first light dope epitaxial loayer that exposes;

The gash depth of the thickness of formed the second light dope epitaxial loayer for forming.

The 6th step, adopt wet method or dry etching technology, return and carve silicon dioxide to needed thickness, form the thick grating oxide layer of groove and bottom thereof.

The technique effect that the present invention can reach is:

The present invention adopts selective epitaxial growth to form groove, and returns the thickness that the oxide layer in the ditch groove extremely needs, to serve as the thick grating oxide layer of channel bottom.

The present invention can make bottom thick grating oxide layer trench MOS structure easily form and control, and can accurately control the position of the relative groove of epitaxial loayer of double-deck extension groove MOS, thereby can by controlling respectively the doping content of two-layer extension, come puncture voltage and the on state resistance of optimised devices.

Description of drawings

The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments:

Fig. 1 to Fig. 5 makes the corresponding structural representation of each step of the process of bottom thick grating oxide layer groove MOS with the present invention;

Fig. 6 is the schematic cross-section that adopts the made bottom thick grating oxide layer groove MOS device of the present invention.

Embodiment

The present invention makes the process of bottom thick grating oxide layer groove MOS, comprises the following steps:

The first step as shown in Figure 1, at heavily doped silicon Grown epitaxial loayer, forms the first light dope epitaxial loayer; The heavy doping bulk concentration is 10 ¹⁸/ cm ³Above;

Second step, as shown in Figure 1, the silicon dioxide of growing on the first light dope epitaxial loayer, its thickness is equal to, or greater than the follow-up gash depth that will form;

The 3rd step, as shown in Figure 2, adopt photoetching process, gluing, photoetching on silicon dioxide form photoetching offset plate figure;

The 4th step, as shown in Figure 3, etching, the silicon dioxide etching of not blocked by photoresist is clean, expose the first light dope epitaxial loayer beyond photoresist; Then remove photoresist;

The 5th step, as shown in Figure 4, selective growth the second epitaxial loayer; At the superficial growth second light dope epitaxial loayer of the first light dope epitaxial loayer that exposes, and do not grow on silicon dioxide;

The thickness of the second light dope epitaxial loayer is to want the gash depth that forms;

The 6th step, as shown in Figure 5, adopt existing wet method or dry etching technology, return and carve silicon dioxide to needed thickness, namely form the thick grating oxide layer of groove and bottom thereof;

The silicon dioxide that remains is namely as the thick grating oxide layer of channel bottom;

Adopt the present invention, can make groove MOS device as shown in Figure 6.

Claims

1. a process of making bottom thick grating oxide layer groove MOS, is characterized in that, comprises the following steps:

2. process of making bottom thick grating oxide layer groove MOS according to claim 1, is characterized in that, the thickness of the formed silicon dioxide of described second step is equal to, or greater than the follow-up gash depth that will form.

3. process of making bottom thick grating oxide layer groove MOS according to claim 1 and 2, is characterized in that, the gash depth of thickness for forming of described the 5th formed the second light dope epitaxial loayer of step.